Self Help

Hypothesis-Driven Development

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Matheus Puppe

· 93 min read

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  • The book is titled “Hypothesis-Driven Development: A Guide to Creating Digital Products that Matter” by Alex Cowan.

  • It introduces the concept of Hypothesis-Driven Development (HDD) as an approach to building digital products and running a digital product pipeline from idea to release and experimentation.

  • HDD emphasizes basing product decisions on evidence from customer data and experiments rather than gut feelings or opinions.

  • The book is divided into two parts - the first covers running a digital product pipeline using HDD principles, including chapters on design, development, releases, and experimentation.

  • The second part applies HDD to key practice areas like programming languages, infrastructure, data/ML, security, growth hacking, and revenue operations.

  • Each chapter provides an overview of the topic, discusses anti-patterns to avoid, and recommends practices.

  • The book includes guest editor introductions and perspectives for some chapters from industry experts.

  • The goal is to help readers apply an evidence-driven and customer-centric approach to building digital products and services.

  • The author discusses how the business of technology is changing and more non-technical generalists are now taking on impactful traction roles in tech companies like product management.

  • Coding skills themselves are not as critical as knowing how to develop testable hypotheses about what you want to achieve and then finding technical ways to make it happen.

  • The author positions himself as a generalist who doesn’t neatly fit into one role, having experience in engineering, management, sales, etc. This has helped him understand how to make companies, products and teams successful.

  • He teaches the concept of hypothesis-driven development to help both technical and non-technical people drive wins in digital products and businesses.

  • The author believes being a curious generalist willing to dive into new topics is a “superpower” in today’s world. His goal is to equip interdisciplinary generalists to do high-impact work in technology.

  • Key capabilities to cultivate include hypothesis-driven thinking, learning technical skills iteratively as needed to test ideas, and taking on meaningful responsibility for driving revenue and investing in costs.

So in summary, the author argues technical expertise alone is no longer enough - generalists can play impactful “traction roles” by applying hypothesis-driven approaches to problem solving in technology.

  • Hypothesis-driven development (HDD) is introduced as an approach that helps both technical and non-technical people collaboratively work on “technical” projects.

  • HDD focuses on explicitly stating intentions, linking intentions to specific observations and inferences, and making decisions iteratively based on testing ideas in small batches.

  • This helps generalist managers engage with technical teams by focusing the discussion on shared goals and evaluation methods rather than technical details.

  • HDD advocates for testing ideas quickly through experiments rather than extensive analysis or “analysis paralysis.” Fortune favors the bold through iterative learning.

  • Strategic planning has reduced importance for startups but some anchor for priorities is still needed. HDD helps provide this by linking goals to specific tests and outcomes.

  • Concepts like product/market fit, business model canvas, and OKRs can further help communicate priorities across a company and align individual team work to overall innovation goals.

So in summary, HDD is presented as a collaborative and intentional approach that helps both technical and non-technical stakeholders work together on innovation through explicit hypotheses, empirical testing, and continuous learning.

Here is a summary of the key points about hypothesis-driven development (HDD) and how it relates to agile practices:

  • HDD focuses on testing hypotheses through experiments rather than following a predefined plan. This allows teams to make data-driven decisions at every step from technology choices to user behavior testing.

  • Most digital product teams follow agile principles of self-organizing, cross-functional teams working in short iterations to deliver working software.

  • The core agile principles emphasize individuals and interactions, working software, customer collaboration, and responding to change.

  • Common agile practices include sprint iterations, daily stand-up meetings, and prioritizing work in a backlog using user stories.

  • HDD can be applied within the four primary areas of an agile product pipeline: continuous design, application development, continuous delivery, and hypothesis testing.

  • Each area has key performance metrics like features released, engagement, and release frequency. HDD provides a data-driven approach to assessing success and driving improvements across the entire pipeline.

  • Metrics help focus the team but may lack a unified view of overall performance. HDD aims to provide that unified perspective through experimentation and evidence-based decision making.

So in summary, HDD pairs agile’s iterative approach with a test-and-learn mindset to help teams make integrated, data-driven decisions across all aspects of their product development.

  • The passage introduces the concept of an equation or formula called “F” that represents the cost of developing a successful feature.

  • It explains the different terms in the equation - things like team costs, output produced, portion of features that are successful, etc.

  • An example is given where a team’s cost to develop a feature is $5,000 but only 50% of features are successful, so the cost to develop a successful feature is $10,000.

  • While the exact value of “F” may vary between teams, tracking how it changes over time can help teams understand how their practices are improving or declining relative to their business goals.

  • The passage emphasizes that tracking “F” is most useful for teams that have robust discussions after each sprint/iteration to learn and improve both their agile practices and product health.

So in summary, it introduces a formula for calculating the cost of a successful feature and explains how teams can use it, along with agile practices, to continuously improve. The key value is in tracking changes over time rather than getting an absolute value.

  • The book advocates taking a hypothesis-driven approach to running a digital product pipeline from idea to design, development, testing, deployment, and ongoing experimentation.

  • Traditional “batch” decision making leads to high failure rates of software projects, as starting with a bad idea dooms the project. Digital allows for more adaptive, incremental decisions through practices like continuous design and hypothesis-driven development.

  • While best practices like design thinking, agile, and Lean Startup are now well documented, successfully implementing them is still difficult. It requires unlearning old command-and-control habits and creating more fluid collaboration between teams.

  • Part 1 of the book will focus on applying hypothesis-driven development concepts and practices across the key stages of the product pipeline, from idea generation and design to deployment and testing. The goal is to establish a foundation for product teams to continuously and adaptively evaluate their assumptions through incremental development and experimentation.

  • Hypothesis-Driven Development (HDD) is a framework that integrates different innovation practices depending on the situation. It can be applied broadly across the product development pipeline.

  • Continuous Design is one area of HDD practice that focuses on figuring out what to build. It involves methods like design thinking, customer discovery/development, and Lean UX/analytics to test problem diagnosis, demand, and usability.

  • Success in Continuous Design means releasing more features that see high engagement or performance. It’s challenging because it requires an open “growth mindset” rather than just maximizing efficiency.

  • The Double Diamond model is used to decouple problem and solution exploration. HDD applies this model across four hypotheses: the Problem/Persona hypothesis to define the user, the Job-to-be-Done hypothesis to identify their problems, the Demand hypothesis to test if the solution is wanted, and the Usability hypothesis to build an easy interface.

  • Hypothesis testing involves screening interviews with 10-25 users to gather data without statistical significance. The goal is to get feedback to progress ideas, not prove them definitively. Done well, it can eliminate ideas or provide direction for the next step.

  • The passage discusses using subject interviews to explore and test persona and jobs-to-be-done (JTBD) hypotheses.

  • It recommends sequencing questions from most general to most specific to avoid leading subjects to particular answers.

  • An example interview guide is provided for a persona named “Trent the Technician”. It includes screening, persona hypothesis, JTBD hypothesis, and example persona and JTBD descriptions.

  • It notes the economic significance is to minimize waste and maximize chances of success by ensuring the persona exists and problems matter, otherwise it would be a waste of resources.

  • A dramatization example is given of a team learning the technicians don’t care about centralized documentation as initially hypothesized.

  • It discusses the difficulty is overcoming habitual, emotional tendencies to immediately prototype rather than validate hypotheses through research first.

  • The goal is to do “just enough” research to test hypotheses before proceeding to further work, rather than treating personas as a finished foundation upfront.

So in summary, it provides guidance on using subject interviews to properly explore and test persona and JTBD hypotheses before proceeding, in order to prevent wasting resources on invalid assumptions.

  • Continuous Design and HDD (human-centered design) emphasize regularly testing hypotheses about customers and demand through minimal prototypes and experiments. This helps ensure teams focus on the right problems.

  • Early on, teams should thoroughly research personas and jobs-to-be-done (JTBD) to define the right problem. Later on, as understanding evolves, revisiting this research can provide valuable insights.

  • Design sprints are a good way to structure short research and testing cycles. Teams should not overdo early research but underdo it later when questions emerge.

  • Common pitfalls include focusing on tangible outputs over outcomes, outsourcing or overdoing early research, or not explicitly testing hypotheses.

  • Effective demand testing aims to generate evidence of demand with minimum waste. Simply asking customers is usually invalid. MVPs allow experiments like smoke tests to definitively answer hypotheses.

  • Archetypes like concierge, wizard of oz and smoke test MVPs provide strategies to structure minimal, testable experiments of demand hypotheses. The goal is to pivot or persevere based on clear pass/fail thresholds.

  • Click-through, purchase, or sign-up are examples of metrics that can be used to test the effectiveness of a minimum viable product (MVP). These metrics indicate if users are engaging with and responding to the core value proposition being tested in the MVP.

  • Click-through rate, which measures the percentage of users who click on a link, is one metric commonly used. A startup may consider a click-through rate of 3% or higher as validation that the concept being tested is promising and worth further development.

  • These metrics provide an early, low-cost way for startups to test hypotheses about customer demand and interest before investing significant resources into building a full product. They help startups avoid spending years and millions on concepts that ultimately don’t resonate with users.

  • User stories are best when decomposed into smaller, testable child stories. Sketching a storyboard can help with this transition from epic to smaller stories.

  • These child stories can then be used directly as test items. Anyone on the team can draft a simple usability test plan and prototype in a tool like Balsamiq to test the stories.

  • It’s important to craft test prompts that don’t lead the user but instead align with the underlying intention of the user story.

  • One example showed decomposing an epic user story into child stories, associated test prompts, and an early clickable prototype.

  • To arrive at prototypes, teams look at comparable websites and apps, capture them visually, note good/bad patterns, and develop parallel concepts to test.

  • Iterative testing of prototypes with users is key, allowing for small corrections rather than overhauls. One example showed a minor annotation fixing a usability issue.

  • Incorporating exploratory usability testing into agile processes helps avoid waste and improves collaboration.

  • Anti-patterns include using usability tests to validate ideas rather than explore usability, and only doing late-stage validation testing.

  • Success looks like continually diagnosing users’ relationship to the application and doing just enough testing to feel reasonably sure of being on the right track.

  • The article describes how hypothesis-driven development (HDD) can be applied to the continuous design process through testing hypotheses about personas, jobs-to-be-done, demand, and usability.

  • Persona and JTBD hypotheses are tested through discovery interviews to understand user needs, goals, current alternatives.

  • Demand hypotheses are tested using minimum viable products and experiments like concierge, smoke, and wizard of oz tests to validate problem/market and product/proposition fit.

  • Usability hypotheses are tested through exploratory and assessment usability testing and analytics to iteratively improve prototypes.

  • Donald Norman’s framework of 7 steps of user cognition is applied toanalyze the user experience at each step: goal, plan, specify, perform, perceive, interpret, compare.

  • Anti-patterns of HDD include building prematurely without proper testing, hedging instead of testing and adapting quickly, and keeping expensive talent busy without investable hypotheses to test.

  • Continuous design and small, frequent batches allow for adaptive design based on evidence rather than big assumptions and help avoid getting locked into bad ideas.

The passage talks about achieving a good definition of done in continuous design and product development. It emphasizes the importance of linking user stories to relevant analytical questions and metrics in order to determine what constitutes “done” and priorities for the next iteration.

It provides an example table showing how individual user stories for an HVAC app could be paired with analytical questions, metrics, and experiments to evaluate the success of that particular feature. Some examples include conversion rates, customer satisfaction, and billable hours metrics.

The key lessons are pairing solutions with relevant metrics and questions focused on user behavior rather than just user feedback. This allows teams to exit each iteration with a specific view on priorities and what constitutes achieving the goals of that iteration. An outcome-based definition of done is emphasized over simply completing features.

  • The passage discusses how MBAs of the future (2030) will differ from MBAs today. Today’s MBAs are more environmentally sustainable, skeptical of big business, and comfortable with trial and error compared to past generations.

  • However, the skills being taught in business schools have not fully caught up to these shifts in mindsets. Schools are still producing “analyzers” rather than “experimenters”. Design thinking and agile/lean startup methods are helping but more progress is needed.

  • Educators still lack the proper tools to help students navigate the necessary changes in both mindsets and skills. However, books like the one mentioned can help advance education in this area.

The key points are that future MBAs will have different mindsets than past generations due to cultural shifts, but the way they are taught still needs to evolve further to properly align with these mindset changes and produce graduates with the right skillsets for the future.

  • When going from design to code, it’s important to have clear goals and outcomes in mind before starting implementation. This gives direction and prevents getting lost in the details.

  • The three core activities are: 1) Unpacking the design into specific, code-ready steps; 2) Choosing a viable solution by weighing options like building from scratch, borrowing code, or using third-party tools; 3) Analytically debugging and testing to arrive at a working version.

  • Views (the user interface) are often built with HTML and CSS, which use elements like

    to define functional components and CSS to configure properties like styles.

  • It’s important to break down user stories and designs into specific HTML elements and CSS properties to lay out the interface. Elements like tag to define the dropdown and

  • It explains how CSS can be used to style these elements uniformly, through classes or IDs, avoiding having to manually style each instance. A CSS class is defined with a ”.” prefix and grouped styles within curly braces.

  • WYSIWYG (What You See Is What You Get) editors like those in WordPress allow editing HTML and CSS visually without dealing with the underlying code. They provide abstractions to manipulate the code.

  • Such editors are useful for quick builds but have limitations. For more control, one needs to work with the raw HTML and CSS directly.

  • In summary, it’s good to learn HTML and CSS fundamentals to have more flexibility, even if WYSIWYG editors can handle basic visual editing tasks.

Here is a summary of the key points about L and CSS:

  • HTML and CSS are commonly used to build views/user interfaces for digital applications like websites and web apps. The majority of views are built using HTML and CSS or similar technologies.

  • If you’ll be working on product teams developing digital applications, it’s useful to learn basic HTML and CSS coding skills. This allows you to more easily participate in collaborative development work and make small changes to views without bugging developers.

  • HTML and CSS are good first technologies to learn because they are universally used for web views. While other technologies are used for native mobile and desktop apps, HTML and CSS skills translate well.

  • Once you get past the initial learning curve, many find coding with HTML and CSS can be an enjoyable creative process, even if just tinkering with it occasionally.

  • CSS in particular is important for responsive design - allowing views to adapt and resize for different screen sizes from desktop to mobile. Frameworks like CSS Grid help with responsive design.

  • HTML and CSS, along with tools like JSFiddle, allow prototyping and testing views through an iterative development process of formulating and testing hypotheses.

So in summary, HTML and CSS are core technologies for building digital application views, and gaining basic proficiency in them is useful for many roles on product teams developing web and mobile applications.

  • The passage discusses using algorithms and functions to build controllers that connect user interfaces (views) to application logic and data.

  • An algorithm is described as a set of discrete steps to accomplish a goal. Thinking in algorithms involves breaking down user intentions into discrete steps.

  • A simple example algorithm is given to check if the garbage needs taking out based on fullness and smell.

  • The algorithm is then coded as an “if-then” statement in JavaScript to check credits needed for graduation. Console output is used to test the logic.

  • Functions are described as the building blocks of controllers. They take inputs, execute coding steps, and return outputs.

  • A function called “grad_credits” is created that takes a credits value as input, checks if it is above the graduation requirement, and returns a string output stating if the student can graduate or needs more credits.

  • The function is called from other code and the return value is stored in a variable and checked with console output to test the function logic.

So in summary, it introduces the concepts of algorithms, if-then logic, functions, and variables as key elements for building controllers that connect user interfaces to application logic and data. Simple JavaScript examples are provided.

Here are the key points about how the View and Controller interact:

  • The Controller listens for user interactions/events from the View, typically using event listeners. For example, it listens for clicks on buttons.

  • The Controller can get data from and set data on the View. For example, it can retrieve the selected values from dropdown menus in the View.

  • The Controller manipulates the underlying data/model and then updates the View accordingly. For example, filtering a list based on user selections in dropdowns and hiding/showing items in the View.

  • Libraries/frameworks provide helper methods to more easily retrieve/update View elements from the Controller. For example, jQuery has methods to get/set element attributes and values.

  • The View renders/reflects the state of the model/data but is separate from the Controller logic that manipulates the data. This separation of concerns is a key part of MVC.

  • Common interaction patterns include the Controller listening to View events and updating the model/data, then the View re-rendering based on the new state. The data flow is Controller <-> Model <-> View.

So in summary, the Controller handles app logic and integrating user input from the View to update the model/data, while the View simply displays what’s in the model and allows user interaction like clicking buttons. Events and data binding facilitate the interaction between the two.

Here is a summary of the key points about JavaScript from the passage:

  • JavaScript is a popular and versatile programming language, but it is not every developer’s favorite and most applications are not created in JavaScript.

  • Learning JavaScript is a good starting point for generalists to learn how to go from design to code. Getting practice with JavaScript will develop intuition and empathy that can be applied to collaborations.

  • Coding well takes a lifetime of learning as there are many ways things can go wrong, especially at large scale. A focus on solving current problems and refactoring as needs are learned is better than over-engineering for unknown future needs.

  • Important concepts include not building systems without test automation, avoiding too much custom code by leveraging existing libraries/APIs, and preventing duplication of code or functionality.

  • Structuring data models is important for collaboration but changes should be made incrementally as understanding improves, focusing on modeling real world entities and relationships. Relationships like has-a and is-a help describe data relationships.

  • Database concepts like naming, normalization, and keys are important for general understanding to help explain data models to teams. Normalization involves storing logically related data together without unnecessary dependencies between fields.

Here is a summary of the key points about managing data in the Model layer from a database perspective:

  • The Model layer is where application data is defined and stored. This typically involves managing database tables and relationships between tables.

  • Normalization is important to avoid data errors or “anomalies”. It involves structuring the database into multiple tables and only storing each piece of data once. This reduces redundancy and improves data integrity.

  • Common database types include relational databases (like SQL) and non-relational/NoSQL databases like document databases. Relational databases use tables linked by keys/foreign keys while document databases store data in JSON-like documents.

  • Queries (SQL statements) are used to retrieve and manipulate data across related tables by keys/columns. For example, to lookup a distributor for a manufacturer.

  • Each table has a primary key to uniquely identify rows. Natural keys use a unique attribute like a part number. Surrogate keys are arbitrary IDs generated by the database.

  • Database design considerations include performance, security, availability, change management, and coupling between code and schema changes.

  • The goal is to implement a data structure and access interface that maximizes flexibility for changes while minimizing disruption to ongoing development.

So in summary, the Model focuses on managing application data through database design, normalization, queries and keys to support the higher level application logic in a maintainable way.

  • Continuous delivery and deployment aims to improve the process of moving code changes from development to testing to production release. It helps teams learn faster and avoid manual work and emergencies.

  • DevOps is an extension of agile principles specifically focused on how developers and test/deployment teams can work better together. Like agile, DevOps is a philosophy rather than a strict process.

  • Continuous delivery provides value by allowing much more frequent releases, often multiple times per day. This puts hypothesis-driven development into overdrive.

  • Manual, infrequent releases are problematic and cause stress for teams. The author experienced these issues firsthand as both an engineer and founder.

  • Transitioning to continuous delivery requires changes across the whole team and product pipeline. It can’t be fixed by just one “DevOps engineer.” Support from leadership is important for the changes to be successful.

  • Upcoming sections will discuss the specifics of testing and deploying as part of a continuous delivery approach. This helps achieve the goal of efficiently moving code changes through the full product development cycle.

Here is a summary of the key points about the evolution from traditional software development processes to continuous delivery:

  • Traditionally, development (Dev), testing (Test), and operations (Ops) were siloed functions that passed code through handoffs. This resulted in long lead times between writing code and deploying updates.

  • The rise of software-as-a-service (SaaS) models, where vendors host applications online, helped drive closer collaboration between Dev and Ops teams. This is because SaaS teams operate the software they develop.

  • Configuring and deploying applications to different customer environments was complex and error-prone under the traditional enterprise model. Variations in operating systems, libraries, and networking configurations challenged deployability.

  • The DevOps movement emerged to break down silos between Dev, Test, and Ops. It emphasizes automation, monitoring, and collaboration across these functions to enable continuous delivery of updates.

  • Tools like Docker and Kubernetes emerged to standardize application environments and automate deployment. This reduces configuration issues and handoffs between teams.

  • Continuous delivery aims to make software updates safe, automated, and frictionless through practices like test automation, infrastructure as code, and monitoring. The goal is deploying updates more frequently and with high reliability.

So in summary, the evolution has been from segmented, handoff-based processes to integrated, automated practices centered around continuous delivery of updates through collaboration between development and operations.

  • DevOps aims to minimize handoffs and maximize automation in the software development process. This includes automating testing and deployment.

  • Version control systems like Git and GitHub allow multiple developers to work on the same codebase collaboratively without conflicts. Developers each work on their own branches and then merge changes back into the main branch.

  • Merging changes from multiple developers risks merge conflicts if changes overlap the same lines of code. Small, frequent merges are less likely to cause conflicts than large merges covering a long period of work.

  • Teams use pull requests where a developer requests their branch be merged but another developer reviews the code changes first before completing the merge. This encourages peer review of code.

  • Automating the development process through continuous integration/delivery allows much more frequent deployments while reducing bugs, according to studies. This improves metrics like deployment frequency, lead time, downtime, and failure rates.

  • The DevOps approach emphasizes putting everything related to the development and deployment process under version control, even things like passwords and authentication tokens, to encourage transparency and collaboration.

  • Version control is linked to the product pipeline, with code being checked in and out of branches and builds proceeding through testing and deployment.

  • Testing is a key part of the DevOps approach and aims to invest in test automation to lower friction in releases and improve feature velocity. However, adding test automation may initially slow things down due to technical debt.

  • Technical debt refers to shortcuts taken in development for speed that compromise quality and maintainability over time. It manifests as features taking longer to develop as technical debt accumulates.

  • Teams should aim to minimize technical debt by periodically paying it down through refactoring. Lack of test coverage and unpredictable feature costs are signs it may be time to pay down debt.

  • The test pyramid model advises prioritizing unit tests, which provide the most targeted results, followed by integration and system tests higher up which have less isolation but are important to test as well.

  • System or large tests simulate how a real user would interact with the application from end to end. They test the overall user experience and workflows, but take a long time to run.

  • Integration tests test how different functions or components interact with each other. They focus on the inputs, outputs, and interactions between two functions. Integration tests are generally written by developers.

  • Example integration tests are shown testing functions that check if an email address is from an approved domain. The tests supply different example emails and assert whether the expected true/false result is returned.

  • Integration testing frameworks like JUnit (Java) and Jasmine (JavaScript) help structure and write integration tests more efficiently. Teams aim for iterative test coverage by analyzing what level of test could have caught any bugs.

  • In summary, integration tests verify the interactions between code components, sitting in the middle level of the test pyramid between unit and system/end-to-end tests in terms of scope and speed. They help catch bugs at the interface between functions.

Here is a summary of the key points about the Jasmine framework and its usage in integration testing:

  • Jasmine is a JavaScript testing framework that allows you to write automated tests for JavaScript code.

  • The top-level function is describe(), which takes a descriptive name for the test suite and a set of it() function callbacks as inputs.

  • The it() functions each represent an individual test case. They take a descriptive name and a set of functions (the actual test code) as inputs.

  • Within each it() function, expectations about the output are made using the expect() function. expect() allows you to make assertions about the outcome of the code being tested.

  • So in summary, describe() wraps multiple it() tests, and each it() contains one or more expect() assertions to validate the code’s behavior for that test case.

  • This nested structure provides an organized way to logically group and execute related tests as part of an integration testing strategy using the Jasmine framework.

  • DevOps approaches deploying software with a focus on uptime and velocity/frequency of deployments. The goal is to deploy changes rapidly while minimizing downtime and errors.

  • Automated testing, deployment pipelines, and feature flags help enable more frequent deployments with less risk. Some research shows teams can deploy more often and have fewer production issues with an automated pipeline.

  • Deployment roles include ops engineers, SREs, and DevOps engineers. Their job is to create self-service infrastructure and automation tools that product teams can use to deploy on their own.

  • The “jobs” of the deployment team include: designing system topology and standards, developing automated infrastructure code and deployment processes, operating and maintaining the infrastructure, and providing customer/user support to internal product teams.

  • Effectively, deployment teams act as their own “product team” - managing requirements, design, development and support of the shared deployment infrastructure product that internal teams consume.

So in summary, DevOps prioritizes deployment velocity and uptime through automation, and focuses deployment roles on empowering product teams through self-service infrastructure and tools.

  • The team is working on automating the infrastructure provisioning process to install and configure new hosts and dynamically scale resources as needed.

  • They are creating standardized “host profiles” to configure developers’ local machines the same way the code will run in production, eliminating configuration differences.

  • Deploying code typically requires more manual work for teams transitioning to DevOps. The goal is to automate deploy processes.

  • Maintaining involves minimizing production issues and resolving them quickly through automation. Learning from issues to improve processes.

  • Technologies like Docker containers, VM virtualization, cloud computing allow standardizing environments to eliminate “it works on my machine” issues and enable automation.

  • Automation tools configure servers, deploy applications through configuration management tools like Ansible, Puppet and Chef. Orchestration with Kubernetes further automates scaling applications across infrastructure.

  • The platform manages applications dynamically by monitoring the overall resource pool and scheduling application instances accordingly. It aims to rebalance workloads dynamically to maximize resource utilization.

  • For mobile and non-web app deployments, while the deployment steps can be automated, the actual updates/installs depend on the end user’s device and choices. However, these apps often have server components that can be deployed using the same processes.

  • Security is important throughout the development and deployment processes. Tests should include security testing, and deploying credentials/access management is a key focus area.

  • Continuous integration/delivery (CI/CD) tools like Jenkins help automate connecting the development, testing and deployment processes to enable continuous deployment pipelines. They facilitate automating builds/tests and deploying code changes.

  • Teams should clearly map out their existing development to deployment processes, hold retrospectives to improve, and work to standardize environments and automate manual steps to progress towards continuous delivery.

  • Accumulating technical debt by not investing in your product pipeline will steadily degrade your release time and success rate over time. Regular, incremental improvements like improving testing and deployment processes can improve velocity and reduce friction.

  • When things aren’t working as intended, the natural reaction is to want to fix them quickly according to your own plan. However, steady incremental changes developed collaboratively with the team through retrospectives tend to be most effective.

  • Sketching out your current product pipeline in detail is important for understanding where improvements can be made. Prioritize testable, timeboxed changes and establish criteria for success/failure.

  • An agile team charter can document your current processes and point of view to make them explicit and amenable to change.

  • Fundamentals of DevOps and continuous delivery like version control, automated testing, and managing work in a production-like environment are important to understand.

  • Starting small, getting feedback quickly, and iterating is the best approach to adopting new CI/CD practices rather than a big bang change. Testing changes in production is an emerging trend to validate user experience.

  • The passage discusses the importance of integrating experimentation across the entire customer experience, from early discovery and design through product release and analytics. This is becoming a core skill for product teams.

  • It highlights challenges like Google Flu Trends, which drastically underpredicted a flu season due to issues understanding the “ground truth” of user data. Hypothesis-driven development can help address these challenges by connecting qualitative and quantitative evidence.

  • Tools like Optimizely and Google Optimize have made experimentation easier to implement. Best practices include having a culture of experimentation where teams continually run and learn from many concurrent experiments, as seen at companies like

  • High-functioning agile teams focus on measurable outcomes rather than just outputs. They bring specific observations and ideas for metrics to iterations. Self-service experimentation infrastructure helps scale a culture of experimentation across many teams.

  • Tables contrast traits of low vs. high-functioning teams, showing how the latter closely integrates analytics, experimentation and learning into all aspects of product development and operations.

So in summary, the passage advocates for integrating experimentation throughout the product development process using approaches like hypothesis-driven development and best practices from companies with strong experimentation cultures.

  • The team leads with hypotheses about causality that are well-articulated, reasonably observed, and consistent with experimental design and results. They question even promising statistics if there isn’t a plausible causal explanation.

  • To improve, the team starts with small but purposeful experiments, learns from successes and failures, and builds on what works. Not every experiment will immediately improve outcomes.

  • Framing hypotheses for testability is important for an evidence-based approach. The dependent variable (DV) is the outcome being predicted or forecasted based on independent variables (IVs). The relationship between DV and IVs may indicate correlation or causation.

  • Without understanding causation, actions taken based on correlations alone could have unintended consequences. Continuous experimentation and questioning findings helps address this.

  • Focusing on the right DV makes inferences more actionable. For example, instead of just forecasting ice cream sales over time, focusing on optimal staffing levels by hour could better inform scheduling decisions.

  • The right DV depends on the intended intervention and who needs to take action. Aggregate metrics may not always reflect customer experience or satisfaction with a specific task.

In summary, the team emphasizes hypotheses about causation, learns through experimentation, and focuses on making inferences actionable by choosing the most relevant dependent variables. Continuous improvement relies on questioning assumptions and being open to being wrong.

  • When designing experiments to test hypotheses, it’s important to consider the desired inference, experimental design, necessary observations/data, and economic value/actionability of results.

  • Three common experiment patterns are discussed: retrospective case-control (RCC), prospective cohort study (PCS), and randomized controlled experiment (RCE).

  • RCC analyzes existing observational data to look for associations between independent and dependent variables, without proving causation due to potential confounders. However, it allows quickly evaluating hypotheses.

  • Examples of using RCC for a baldness hypothesis test are described, with “bald” as the case and “haired” as the control. Association between balding and lemon juice shampoo use would be assessed.

  • While not proving causation, RCC can help prioritize which hypotheses to test further with more rigorous methods like PCS and RCE that allow stronger causal inferences. The goal is economically actionable conclusions to guide business decisions.

In summary, the key points are about appropriately designing experiments to test hypotheses in a way that provides economically useful conclusions, considering different experimental designs and their inferences, data needs, and value. RCC is discussed as an initial observational method before stronger designs.

  • A prospective cohort study (PCS) observes a population that differs in their exposure to the independent variable (IV) of interest, such as using shampoo with or without lemon juice.

  • Subjects self-select into cohorts based on their choice regarding the IV (lemon juice shampoo use). One cohort uses lemon juice shampoo while the other does not.

  • Researchers then observe the development of the dependent variable (DV), such as baldness, in the cohorts over time.

  • The PCS allows researchers to infer an association, not causation, between the IV and DV by asking what the likelihood of baldness is for those using lemon juice shampoo compared to those who do not.

  • Unlike a retrospective case-control study, the PCS is a controlled study where researchers design how subjects interact with the IV. It provides more opportunities to understand and control for confounding variables compared to retrospective studies.

  • However, PCS introduces a delay between cohort assignment and DV observation, while retrospective studies can analyze existing data more quickly. Both study types still only show association, not causation.

  • In an A/B test experiment to test adding a live chat feature on their app, the HinH team aims to increase the order rate (visits with orders/total visits) among technicians who currently order at a rate below 30%.

  • They will randomly assign some technicians to see the chat feature (test group) and others to not see it (control group). This is a randomized controlled experiment design.

  • The team’s pass/fail threshold is a 10 percentage point increase in order rate, as that would make staffing the live chat cost-neutral.

  • To decide whether to expand the chat feature, the team needs enough data to make an informed inference. There are two main statistical approaches to making inferences from experiment data: frequentist and Bayesian.

  • The number of observations (sample size) needed depends on which inference approach is chosen and how it is applied. The team will need guidance from stats experts to determine the optimal sample size and approach given their specific experiment goals and context.

  • The passage describes the frequentist and Bayesian approaches to statistical inference.

  • Frequentists try to assess if an independent variable changes a dependent variable or if observed variations are just random chance. They define null and alternative hypotheses and use hypothesis testing like t-tests.

  • Problems with the frequentist approach include not specifying required levels of certainty or minimum effect sizes needed, which can lead to too few or many observations.

  • These issues are analogous to flaws in vague software development processes.

  • To solve this, the experiment design should define the desired level of certainty, minimum effect size, and the acceptable probability (α) of wrongly rejecting the null hypothesis.

  • For agile digital experiments, aiming for 70% certainty rather than the typical 95% may be reasonable given low data costs. However, α still needs to be set to take a hypothesis-driven approach and standardization helps with experiment interpretation.

  • In summary, the passage advocates for hypothesis-driven experimental design informed by Bayesian thinking to address flaws in common frequentist practices.

  • The passage discusses frequentist versus Bayesian approaches to statistical analysis for A/B testing in digital product experiments.

  • It explains the limitations of a frequentist t-test in just telling you if an observed effect is random noise or not, but not confirming if it meets a pre-specified goal like a 10 point increase in orders.

  • It introduces the concept of type I and type II errors and how power calculations can determine the needed sample size to achieve a desired balance of being wrong.

  • Common frequentist conventions are an alpha of 0.05 and beta of 0.2, but it argues beta should be lower for digital experiments to avoid missing potential big wins.

  • It calculates a needed sample size of 216 for Frangelico’s experiment based on values of alpha=0.3 and beta=0.15 to have 85% power to detect their desired 10 point order increase.

  • It then introduces the Bayesian approach as better suited for digital experiments, as it can directly test hypotheses about meeting pre-specified goals using prior data rather than just detecting non-random effects.

So in summary, it explains frequentist statistical techniques, their limitations for digital A/B tests, and introduces the Bayesian alternative as a better model for the rich, continuous data and product optimization goals in digital experimentation.

  • The Bradford Hill criteria provide guidelines for evaluating whether an observed association is likely causal or not. They were originally developed for public health but are now widely used in data science and machine learning as well.

  • The 9 criteria are: strength of association, consistency, specificity, temporality, biological gradient, plausibility, coherence, experimentation, and analogy. These criteria examine aspects like the size of the observed effect, reproducibility, timing, dose-response relationship, biological mechanisms, and experimental evidence.

  • Meeting several of the criteria increases the likelihood that an observed association can be considered causal, not just correlational. The criteria help move the analysis beyond just finding associations to determining possible causation, even without randomized controlled experiments.

  • They provide a systematic framework for data scientists and analysts to evaluate whether machine learning and analytics results indicate potential causes and effects worth further investigation, rather than just correlations. This is important as questions of data quality, validity and real-world impacts expand with growing use of digital applications.

In summary, the Bradford Hill criteria offer guidelines to assess whether observed relationships found through data analysis and machine learning may indicate causation rather than just association. Meeting several criteria makes causation a stronger possibility even without randomized experiments.

Here are the key points about moving from association to causation with giant data sets:

  • Deep machine learning is good at finding associations in data, but does not necessarily prove causation. There could be unknown confounding factors.

  • Randomized controlled experiments (RCEs) can establish causation, but are often impossible or unethical for things like smoking and health outcomes.

  • Sir Austin Bradford Hill used alternative approaches like relative risk/cohort comparisons (RCCs) and prospective cohort studies (PCSs) to study the causal link between smoking and lung cancer, since RCEs were infeasible. These helped develop criteria for inferring causation from observational data.

  • Observational data from large datasets can provide useful evidence for assessing causality through techniques like controlling for confounding factors, replication in different populations/times, strength of association, biological plausibility, and other Bradford Hill criteria. But causation cannot be definitively proven without experimental evidence.

  • The key is using a combination of different study designs and weighing various lines of evidence to make a reasonable causal determination, rather than relying on any single association or data point in isolation. Causation involves inference rather than definitive proof.

  • The passage discusses user story mapping and A/B testing to optimize a parts ordering workflow for HVAC technicians.

  • It presents a candidate user story mapping that identifies 4 key stories: searching for parts by number, description, or photograph. The lowest priority is searching by photograph.

  • Metrics are proposed to measure success, like conversion rate from viewing parts details to placing an order.

  • An A/B test is suggested to test introducing the lowest priority search by photograph story, to see if it improves or hinders conversion rates.

  • Guidance is given on instrumenting the user flow with analytics to acquire the necessary observations/data for evaluating the metrics and A/B tests. Google Analytics is presented as a popular tool for this.

  • Specifically, it walks through how to define an “event” in Google Analytics to track parts lookups as the key metric of “Lookups/Active User” to measure user engagement.

So in summary, it discusses using user story mapping and A/B testing with google analytics instrumentation to optimize a parts ordering workflow, with a proposed test of a new search method.

  • The passage discusses setting up event tracking in Google Analytics (GA) to observe parts lookups by technicians. It describes creating a custom event in GA called “lookup” to track lookups.

  • It shows how to configure the GA tracking code to fire the lookup event with relevant parameters like part number. This allows lookups to be recorded in GA reports.

  • The goal is to measure a dimension like “Lookups per Active User” over time. More work is needed to create a composite view in GA to show this.

  • When should the event fire? Ideally whenever a valid/successful lookup occurs. Code may need to be added to fire the event at the right time.

  • GA can provide default metrics like user attributes, referrals, page views, events. It focuses on descriptive analytics but also does some diagnostic and prescriptive analytics.

  • Google Optimize allows running A/B tests to help with hypothesis-driven development. An example is testing how adding a third search type affects onboarding and engagement.

  • Common pitfalls discussed are making inferences without actionability, not having an explicit experiment design, not considering effect size, over/under powering studies, and not taking advantage of techniques like Thompson sampling.

So in summary, it covers setting up events in GA to observe lookups, considerations for firing events at the right time, default GA metrics, and using Google Optimize for hypothesis testing as part of a hypothesis-driven development approach.

Here is a summary of the content at

  • It discusses the difference between frequentist and Bayesian statistical reasoning. Frequentist statistics deals with long-run frequency probabilities, while Bayesian looks at updating beliefs based on new information.

  • It provides a link to additional resources for learning more about statistics topics:

  • The chapter was co-authored by guest editors Casey Lichtendahl and Eric Tassone. Brief biographies are given for each, detailing their academic and industry experience in data science and analytics.

  • Three questions are asked of each editor. Casey discusses his path to data science and lessons learned about generalist engagement with data science teams. Eric discusses how he got interested in statistics after law school and what he learned about embedded quantitative problems from working at Google.

  • The key topics covered include frequentist vs Bayesian statistics, the guest editors’ backgrounds, best practices for generalist collaboration with data scientists, and ongoing areas of research interest like bridging statistical approaches and data science applications at the business/product intersection.

  • The passage discusses how to decide where to experiment next with your product through continuous design and hypothesis testing in an agile development process.

  • It emphasizes having a consistent context for prioritizing areas of focus through a Customer Experience (CX) map. This map should motivate questions about how to improve user outcomes and behavior.

  • An example CX map is provided for an HVAC technician using a new self-service parts ordering app. A storyboard walks through the user experience from trigger to action to reward.

  • Details are noted for each step of the storyboard regarding current understanding, open questions, and specific metrics or observations to track user behavior.

  • Careful instrumentation of user data is advised to gather evidence on things like how many orders are dropping out or why users may not continue using the system after an initial trial.

  • The goal of the CX mapping and storyboarding process is to facilitate shared team understanding and focus experimental efforts on addressing the right questions to improve the product iteratively based on testing results.

Here are the key points about using a customer experience (CX) map for quantitative observability and experimentation:

  • The CX map outlines the customer journey from acquisition to outcomes in a structured way. It defines stages like onboarding, engagement, retention, and outcomes.

  • The metrics should focus on economic value rather than just model accuracy. For example, balancing inventory costs vs stockouts, or maximizing lifetime customer value from churn interventions.

  • Each stage has a dependent variable (DV) metric to measure, like ratio of online orders to total orders for the engagement stage.

  • “Lines in the sand” set target thresholds for the DVs to guide experimentation, even if adjusted later based on learnings.

  • Hypothesis testing experiments flex independent variables (IVs) like product features to improve the DVs and cross stages/lines.

  • The map needs clear, mutually exclusive stage definitions and measures an individual user’s journey.

  • It focuses on a specific customer need and value proposition to isolate behaviors rather than provide an overall business view.

  • Continuous tweaks to the map refine understandings from observational data and experiment results over time.

So in summary, the CX map structures customer behavior observation and linked experimentation to maximize economic outcomes through an iterative, learning-based approach.

  • The CX map serves as a focal point and information radiator for the team to decide where to experiment and how past experiment results inform priorities. It should be highly visible, like on a wall or shared document.

  • While the CX map provides a durable view, it should still change as the team’s understanding evolves based on experiment results.

  • The product/business lead’s job is to do consistent work across qualitative and quantitative observations, making actionable inferences on an agile cadence based on the CX map.

  • For the HinH app, onboarding involves:

    • Finding part pricing/availability (first DV: signups/lookups)
    • Ordering a part (second DV: signups/orders)
  • These onboarding steps are progressive metrics - lookups must occur before orders.

  • Experiments could test things like recent search features or inventory placement based on onboarding metric results.

  • If acquiring users but not engaging them, the focus should be between onboarding and engagement based on the CX map.

So in summary, the CX map guides experimentation and priorities, and onboarding metrics can indicate where to focus improvements between acquisition and engagement.

  • Boarding programs and product iterations refers to tracking how users onboarded or were introduced to the product in different ways (e.g. different onboarding flows). This allows running experiments to test the impact of different onboarding approaches.

  • When testing engagement, the metric is usually something like frequency of usage - do users make regular use of the product part of their routine?

  • Testing outcomes looks at whether users achieved their goals for using the product. Goals need to be measurable. Surveys can help but observing behavior is better.

  • Testing retention looks at behaviors needed to support business goals like revenue, viral growth, or increasing share of wallet over time. The principal “engine of growth” guides which behaviors to prioritize.

  • For HinH, engagement is measured by share of parts ordered online. Outcomes include time to repair, billable hours, and customer satisfaction. Retention focuses on maintaining/increasing share of parts ordered online and peer referrals over time. Experiments focus more on outcomes since retention behaviors are already being met.

So in summary, it involves defining and testing metrics at each stage of the customer journey - onboarding, engagement, outcomes achieved, and long-term retention behaviors aligned with business goals. Quantitative metrics and experiments help evaluate the impact of product changes.

  • Companies are increasingly able to track detailed customer behavior data over time, allowing them to analyze metrics at the individual customer level rather than just aggregate levels.

  • Looking at individual customer cohorts rather than just aggregate metrics can help identify issues like high customer acquisition but also high churn, where overall usage numbers may look good but the customer experience is actually failing for most new customers.

  • Important metrics like customer engagement and retention need to be tracked and evaluated at the individual customer level through tools like a customer journey map.

  • When metrics show problems, the best response is to frame thoughtful questions and do targeted experiments and hypothesis testing through continuous design/delivery processes, rather than just pushing out more features blindly.

  • Hypothesis testing needs to have clear economic actionability - the results must inform decisions that impact revenue or key behaviors. Technical issues can also occur in experimental design and data collection infrastructure.

  • Digital programs often rely on experimentation and interdisciplinary roles/practices. Companies like allow anyone to launch experiments without management permission to foster a culture of experimentation.

  • To encourage strong practices, teams can encourage action and experimentation while limiting the “blast radius” of changes. Issues should be specifically addressed as they arise through collaborative diagnosis of root causes.

  • Speciality teams should define success by delivering useful self-service infrastructure for product teams.

  • Existing data like retrospective case controls can quickly explore associations between variables to inform experimentation investments.

  • In hypothesis testing, issues in other steps like experimental design or too few observations can cascade to look like inference problems. Model selection and explaining concepts are important.

  • Right solution testing examines problem/solution fit, interfaces, usability, and analytics to determine if the solution needs iteration or if the real issue is upstream in continuous design like no demand for the value proposition.

  • If a released product sees no visits, demand hypothesis testing may need re-examination. User stories and experience mapping help transition from demand validation to testable usability hypotheses.

  • High bounce rates after onboarding may indicate the proposition interests users but the current solution implementation is not a fit, pointing to further debugging using models like Norman’s 7 step model of user cognition.

  • The passage discusses different ways that product teams can debug or understand unexpected or confusing results from user testing, particularly with minimum viable products (MVPs).

  • If an MVP like a concierge MVP doesn’t yield clear or converging results, the team should check that they are properly screening users to match the target problem and user profiles defined in hypotheses. Screening criteria may need tightening.

  • For a smoke test MVP with low click-through rates, it suggests tightening user screening/segmentation based on learnings from discovery interviews, or looking at patterns in analytics data like geography or device. Pivoting the problem or solution approach may be needed.

  • It provides an example of how positive early results but poor conversions in an acquisition funnel could indicate a mismatch with the actual customer’s needs or willingness to purchase, requiring a pivot.

  • The key takeaways are to link testing results back to hypotheses, consider whether user screening and recruitment need improvement, and be willing to pivot the problem or solution approach based on ambiguous or unexpected findings from MVP testing. Tightening hypotheses and doing more qualitative research with users can help debug issues.

Here are some key points about how HinH can experiment their way to product-market fit:

  • In sprints 5-6, they released a minimum viable product (MVP) that allows field technicians to place parts orders online, while manually handling the order management behind the scenes. This allows them to test the core value proposition with real users.

  • In sprint 7, they are taking time to clean up technical debt and prepare for supporting real users. This ensures the product is stable enough for experimentation and they can respond to any issues that arise.

  • Going forward, they should establish clear hypotheses about user behavior and business metrics to test. For example, hypotheses around order volume, conversion rates, time spent on site, etc.

  • They can run controlled experiments like A/B tests to refine the user experience and evaluate different solutions. For example, testing different ordering flows or payment methods.

  • Metrics like weekly/monthly active users, orders per user, retention can help indicate if they are gaining traction or need to pivot. Tracking qualitatively through feedback is also important.

  • If early metrics are promising, they may further invest in functionality, sales/support, and marketing to drive growth. But they should remain hypothesis-driven and willing to pivot if data suggests changes are needed.

  • Overall the goal is to iterate rapidly, learn through experimentation, and use data to determine when they’ve achieved product-market fit to scale up the business. Continuing this process will help them refine their solution over time.

  • The team has been testing their new application in test markets for a few sprints to observe usage and user behavior. After the first week live, acquisition is not as high as hoped.

  • In Sprint 8 they analyze data from two regions - St. Louis mandated use while Tampa only announced it. St. Louis saw higher visit and signup rates. However, the sample sizes are small.

  • Interviews reveal the mandate in St. Louis was not strictly enforced. Still, more techs in St. Louis visited the app.

  • In Sprint 9 the team runs a prospective cohort study in Albuquerque. They offer an onboarding session for some techs and observe outcomes. Techs who attended the session had much higher onboarding and engagement rates.

  • While results are still preliminary, the studies provide some evidence that mandates and onboarding sessions can increase initial acquisition and usage of the new application. Larger tests are still needed given the small sample sizes to date.

  • The team tested two treatments (revised email announcement and concierge chat support) in a 2x2 experiment with technicians in three offices.

  • Their goal was to achieve at least a 40% lift in engagement with the new parts ordering tool.

  • The best outcome would be if the revised email alone met this threshold, allowing them to accelerate rollout.

  • If email + chat was needed, they would focus on improving the transition from onboarding to ongoing use.

  • If no treatment was effective, they would reevaluate their approach through design sprints or testing updated assumptions.

  • Lessons from prior sprints informed the new experiments, showing how continuous experimentation and learning can improve outcomes over time.

In summary, the team applied their learnings from previous sprints to design a new controlled experiment, with clear success criteria to guide next steps depending on the results. The emphasis was on continuous improvement through empirical learning.

  • Choosing development platforms, languages, and tools is important for teams, but there is no single right approach - it depends on the specific company and context.

  • As a generalist, it’s important to understand enough about the engineering context to ask the right questions, rather than claiming expertise.

  • The cost of releasing a successful feature (F) is a useful metric to consider. It takes into account both the cost to develop a feature and the success rate of features.

  • F can be calculated using a formula that accounts for team costs, equipment/services costs, output per period, overhead time, and success rate of features.

  • Tracking metrics like number of story points completed per sprint (output per period, fe) and success rate of features (sd) can help analyze changes in F over time.

  • Story point estimates are preferable to time estimates for planning work because software is difficult to precisely predict and estimate complexity rather than hours is more effective. Tracking relative velocity over time is useful for planning without creating a false sense of precision.

In summary, the passage discusses using the metric F (cost of a successful feature) to evaluate engineering work, how to calculate it, and what metrics are useful to track to analyze changes in F over time in an agile context. It emphasizes understanding the context rather than claiming expertise and using story points over time estimates.

Here are the key points about what drives team cost (c$):

  • Outsourcing and offshoring work to lower-cost locations can optimize for c$ but potentially compromise on quality if not done carefully. Relying too heavily on junior developers can increase risks, as seen with Boeing 737 Max software issues.

  • Traditional manufacturing/operational models that optimize costs may not work well for software development where the exact solution is unknown and continuously evolving based on user feedback. Software is only valuable if users actually use and get value from it.

  • Digital products are more sensitive to outcomes/impacts than predefined outputs, as software can become worthless very quickly if not succesful or engaging for users.

  • Factors like location, developer experience levels, and operational processes focused only on reducing c$ can compromise quality, outcomes and true value if not balanced with a focus on continuous learning from users. Outcomes like user engagement and business impacts should be prioritized along with team costs.

So in summary, while team costs are important to consider, overly optimizing for c$ alone through outsourcing, offshoring or relying heavily on junior developers can backfire if it’s not balanced with a focus on outcomes, learning and quality through a product-led approach.

  • Reducing the ratio of custom code that needs to be written from scratch relative to using off-the-shelf components and libraries can significantly reduce the cost and effort required to develop an application.

  • Ways to reduce custom code footprint include codeless platforms that allow building apps through configuration alone, building apps as extensions of existing app marketplaces or platforms, and using basic cloud computing services which provide infrastructure and services without needing to manage servers yourself.

  • The more an application leverages existing infrastructure, components, and platforms, the less custom code needs to be written and maintained, improving metrics like release content per sprint. Codeless platforms require no custom code at all, while building on app stores or as extensions still reduces code footprint compared to managing all infrastructure independently.

Platform-as-a-Service (PaaS) and Backend-as-a-Service (BaaS) allow developers to reduce custom code by using pre-configured cloud services and microservices. With PaaS, developers can ignore maintaining operating systems, libraries, and configurations by using platforms like Heroku that provide helper applications. BaaS provides fully-abstracted backend functions, like authentication with Firebase, rather than building those services from scratch.

To minimize custom code, product owners should engage developers in continuous design through storytelling, prototyping, and analytics to understand user needs. Rather than overly detailed specifications, collaborative conversations help focus development. Storyboards and dot voting during prototyping bring designs to life while inviting developer feedback. Pairing user stories with success criteria in the form of questions and measurable outcomes helps developers work backwards from desired results. Overall, continuous design works best when it radiates useful information to developers and invites their perspectives, instead of just informing them from above.

  • The author advocates for using design systems to reduce handoffs and minimize rework. A design system establishes consistent patterns and components that the development team can access and implement themselves without going through the full design process each time.

  • Examples given are a style guide with colors, fonts, etc. as well as working samples of UI components like search results that include HTML/CSS code. These living documents allow for easy collaboration.

  • The goal is to move beyond a serial design-development process and enable self-service for developers based on documented patterns and standards.

  • Collaboration quality is improved through techniques like design sprints that engage developers directly with users. This enhances understanding of user needs and outcomes.

  • Focusing teams on a single product rather than splitting attention improves results. Despite challenges, remote or agency teams can work if properly integrated and trained in the organization’s practices.

  • Approaches that emphasize project handoffs over cohesive interdisciplinary teams tend to undermine innovation work, which requires deep focus over unpredictably long periods to achieve results. Consistency, flow and full team engagement are prioritized.

  • The concept of “F” represents a team’s overall productivity and output. It is determined by balancing various factors like team composition (c$), engagement (fe), release friction (rf), and stakeholder feedback (sd).

  • In the past, more software development involved large custom coding projects. The agile manifesto shifted focus to collaboration, adaptation, and delivering value.

  • When assessing a team’s performance, it’s important to consider questions around work environment, team preferences, and talent needs rather than just focusing on speed of coding alone.

  • Factors like automated testing, collaborative code reviews, and quick feedback loops can positively impact fe by improving engagement. Manual or inconsistent testing and release processes increase rf.

  • Real-world examples show how considering all factors of F (c$, fe, rf, sd) can provide insights into both high-performing teams making balanced investments as well as challenges faced by teams maintaining legacy systems. Tracking these factors over time helps maximize overall productivity and output.

Here are the key differences between programming languages, frameworks, libraries, and toolchains:

  • Programming languages: Foundational building blocks that define syntax and core functionality (e.g. Java, Python).

  • Frameworks: Provide common functionality and structure for building applications in a language (e.g. Spring for Java, Django for Python).

  • Libraries: Reusable code that implements specific functions (e.g. jQuery for JavaScript, Numpy for Python).

  • Toolchains: Tools and applications used to develop software, like version control, build systems, testing frameworks, etc. (e.g. Git, Maven, JUnit).

The main factors that affect how these stack choices impact team performance (“F”) are:

  • Talent availability - How easy is it to find skilled developers?

  • Stability - How bug-free and reliable are they?

  • Support - How much community/vendor help is available?

  • Relevance - How well do they suit the product needs?

Languages define core abilities while frameworks/libraries provide reusable functionality. Toolchains handle development processes. Together they form the “stack” that determines development speed, quality and maintenance effort over time.

  • jQuery has almost certainly saved billions of hours of developer time by standardizing and simplifying common JavaScript tasks like DOM manipulation and event handling. It is used on over 78% of websites according to a search, making support and documentation readily available.

  • Ext JS has lower adoption (~500 search results vs over 1 million for jQuery), so developers may have a harder time finding support and answers about Ext JS compared to jQuery.

  • Open source components provide benefits but also risks if the project has few contributors and lacks ongoing maintenance. Projects with more developers have less risk of issues like unfixed vulnerabilities.

  • jQuery and AJAX enabled more dynamic and asynchronous website functionality beyond static HTML pages. This was important for features like real-time updates.

  • Node.js allows developers to use JavaScript on the backend as well as the front-end, helping coordinate technologies and leverage existing JavaScript skills across the full stack.

Here’s a summary of the main programming languages discussed and their uses:

  • JavaScript - Dominant for frontend web development and single-page apps due to its role in powering interactivity in web browsers. Frameworks like Angular and React make it easier to manage complex UIs.

  • Python - General purpose language used widely except for frontend work. Known for its clear, readable syntax and broad ecosystem. Popular for data science, automation, web backends, etc.

  • Java - Enterprise workhorse, underlies the Android OS. “Write once, run anywhere” approach appeals to large organizations. Still widely used despite age.

  • C# - Similar to Java but designed for .NET ecosystem on Windows. Integrates tightly with Microsoft products, favored for internal tools and line-of-business apps. Commercial licenses and support.

  • Mobile - Java originally dominated Android, but Kotlin now more common. Swift is the main language for iOS. Frameworks like Flutter allow cross-platform development for both platforms. Overall trend is toward modern web approaches like HTML/CSS/JS.

The key takeaways are that JavaScript reigns for frontends, Python and Java are general purpose heavy hitters, C# favors Microsoft shops, and mobile has shifted from specialty languages toward more standard approaches. The languages tend to mesh well with their target platforms and use cases.

  • Mobile and niche devices like smart speakers are becoming more prominent user interfaces, in addition to traditional computers. Native apps are being reserved for situations where performance or hardware access is critical. Otherwise, it’s common and cost-effective to build mobile UIs with standard HTML, CSS, and JavaScript.

  • For games, Unity is a dominant gaming engine and development platform. It aims to minimize the amount of custom code needed for game development by providing common tools and functionality.

  • Understanding the history and industry context of popular programming languages like Python, Java, and C# can provide insight into how language choices impact a team’s goals and economics. However, team preferences should also be considered.

  • MBAs in a follow-on coding class to the intro course create fully functional web apps projected during a capstone project, like one that analyzes customer support requests using NLP. This shows the skills and projects students can take on with the right training and support.

  • Learning about a company’s existing technology stack from engineers can help product managers understand the economics and constraints of different technical approaches. But the relationship should be collaborative, not one where engineers just execute instructions.

  • Application infrastructure refers to how different components of an application are architected and integrated together, rather than a single monolithic program. This includes things like microservices, APIs, and third-party services.

  • Better application infrastructure enables more flexibility and minimizes costs (“F”) when developing and deploying applications. It allows pieces to be handled by different teams or technologies.

  • Examples given include integrating a messaging module written in a different language, deploying a model build in Python to a web app, and connecting an app to an existing spreadsheet.

  • There is a spectrum from monolithic (single program) to microservices (many separate modules). Microservices trade off increased complexity for more flexibility.

  • For small teams/apps starting out, a monolith is usually simpler. But as teams/apps grow, decomposing into microservices can improve maintainability.

  • Key considerations in choosing an approach include testability, technical consistency, ability to onboard talent, and complexity of systems administration. Microservices are generally more complex but provide more flexibility.

So in summary, application infrastructure refers to how different components are integrated and can enable better development/deployment tradeoffs than a monolithic architecture as needs evolve. The right choice depends on specifics of the team and application.

Here is a summary of how microservices could affect different aspects of a software application based on the given monolith:

Testability: Microservices push more of the testing burden upward to integration and system level tests since functions/services can now span different code modules/services. This makes tests more complex, costly to maintain and run, and reduces problem isolation.

Technical Consistency: Microservices allow for more team autonomy in choosing technologies and stacks, which can reduce consistency. This is good if it improves team fit and productivity, but could introduce more technical debt if used to split an already tightly coupled codebase.

Onboarding New Talent: Microservices effect on onboarding depends on how well consistency is maintained across modules. High consistency makes onboarding easier while loose consistency could make it more difficult. Teams need to assess how architecture changes affect onboarding.

Systems Administration: Microservices increase complexity and make issue diagnosis harder since problems could reside in any service. This increases risk for smaller teams but large companies mitigate it by empowering specialists like SREs to balance development goals.

In summary, microservices introduce benefits like separation of concerns and team autonomy but also risks like reduced testability, consistency and increased operational complexity. The impacts depend highly on the specific codebase, team and organizational context. Regular evaluation is needed to ensure any changes continue to reduce friction (‘F’).

Here are the key points from the summary:

  • The team chose to use a Backend-as-a-Service (BaaS) like Firebase to minimize “F” (the amount of custom code they needed to write) and quickly get a minimum viable product (MVP) out the door to start getting user feedback. This helped increase their user engagement (fe) and reduced time to market.

  • Some pros of using Firebase included better testability thanks to a local emulator, technical consistency since the Firebase SDK is in JavaScript, and reducing onboarding time for new developers given Firebase’s popularity and documentation.

  • Some cons included potentially slower integration tests and added complexity for debugging if issues span both their code and Firebase.

  • They will evaluate if their choice is working as expected by tracking metrics like user engagement over time in retrospectives. No technology decision is permanent - they may need to change course if Firebase isn’t delivering as hoped.

  • An example user flow shows how authentication would work - the frontend code calls Firebase APIs, which handle logging in the user and return responses. Issues could occur between the user and server, or in the application code.

So in summary, the team chose a BaaS to minimize work needed and quickly launch, and will continue evaluating metrics to ensure Firebase remains the best option or if they need to change paths.

  • The LiveSquad startup wanted to provide an opportunity for young people living alone to virtually watch TV shows together through “watch parties”.

  • They chose to build their initial prototype (v1.0) using WordPress because it allows building a basic functional website quickly without much engineering resources. WordPress has themes, plugins and editing tools that reduce custom coding needed.

  • It’s a good option for rapidly testing ideas and product-market fit before investing in a more customized solution. About 1/3 of websites still use WordPress.

  • The FindingFit startup also used WordPress initially and connected it to a spreadsheet model on Google Sheets using the Sheets API. This allowed them to reuse their prototype model without much coding.

  • A student used Flask to deploy a Python data science model as a web app. Flask is a common way to interface machine learning models with the web. Google Cloud Platform helps simplify deploying Flask applications.

  • In both cases, leveraging existing platforms like WordPress, Google Sheets API and Flask allowed the startups and student to focus on testing their ideas rather than extensive custom development for an initial prototype.

Here are the key points about the case study:

  • USSOCOM (United States Special Operations Command) oversees special operations across the US military branches like Army, Navy, Marines, Air Force.

  • Intelligence gathering and analysis is a core activity for USSOCOM to support special operations in the field.

  • The Griffin program was initially created to help analysts across military branches share intelligence and make recommendations.

  • However, over time the Griffin program became outdated and fragmented as it grew in an unplanned way without centralized management.

  • The different systems lacked integration and interoperability, making information sharing difficult for analysts.

  • USSOCOM leadership decided to reboot the Griffin program - they centralized management, adopted common standards, and built a new integrated platform to replace the fragmented systems.

  • The goal was to improve collaboration, access to real-time data, and decision making support for intelligence analysts across all special operations units.

  • Rebooting the program allowed USSOCOM to modernize their intelligence infrastructure and better achieve their mission of coordinating special operations across military branches.

Here is a proposed “target package” that summarizes the ideas and synthesizes them into an actionable recommendation for command:

Recommendation: We recommend pursuing Option 1 - Refactor and Reboot the Griffin program.


  • Option 1 allows us to fully address users’ crucial JTBD of easily annotating and sharing files, which no current solution supports well. This will significantly improve collaboration and data consolidation.

  • A refactored single application built internally gives us the most control over addressing users’ diverse needs and continuously evolving the solution through data-driven design. Integrating feedback into future iterations will be streamlined.

  • While risky, the program’s technical debt and complexity from various third party solutions necessitates a clean break and new architecture. The refactor provides an opportunity to reduce this debt and complexity.

  • Consolidating around a single customizable solution versus various disconnected third party apps allows us to reduce our annual third party software budget by $6 million, freeing up funds for further innovation.

  • Prototyping select point solutions in addition to the core app (Option 3) can help mitigate risk by pilot testing new features before full integration.

Action Plan: We propose an 18-month development cycle for the initial refactor and core 1.0 release. Key activities include:

  • Conducting additional user research and testing to refine requirements
  • Refactoring and rearchitecting the existing codebase
  • Gradually retiring dependencies on third party solutions
  • Releasing in incremental stages to incorporate feedback
  • Piloting select point solutions to evaluate viability for integration
  • Establishing continuous design and agile practices for ongoing evolution

The proposed approach balances risk with opportunity to fully address users’ needs and gain control over the program’s future through an internally developed solution. Regular feedback loops will help ensure we deliver value.

Here is a summary of what happens below the application layer in the network stack:

  • Layer 5 (Session Layer): Manages sessions between applications, including encryption and maintaining multiple streams of communication between client and server.

  • Layer 4 (Transport Layer): Responsible for delivering individual chunks (packets) of application data across the network. Handles packetizing, sequencing, acknowledgments, and retransmissions. Key protocols are TCP and UDP.

  • TCP ensures reliable, ordered delivery of entire data payload by retransmitting lost or out-of-order packets. Used for non-real-time applications like web pages.

  • UDP provides best-effort delivery without acknowledgments or retransmissions, skipping lost data. Used for real-time applications like video calls.

  • Layer 3 (Network Layer): Handles routing and forwarding of packets between networks using IP (Internet Protocol) addresses. Performs tasks like path determination, packet forwarding, routing updates.

  • Layer 2 (Data Link Layer): Delivers data between nodes on the same local network segment or frame. MANages MAC addresses, frames, error checking, and media access. Key protocols are Ethernet, Wi-Fi, etc.

  • Layer 1 (Physical Layer): Defines electrical and physical specifications to transmit raw bit streams over a physical medium like cable, Wi-Fi, etc.

So in summary, layers 4-1 deal with packetization, addressing, routing, error checking and physical delivery of data across networks and between devices.

  • L (Layer) is a protocol that operates at the transport layer to secure communications in a manner similar to SSL. It provides security and encryption of data transmitted over the network.

  • Numbered ports at the transport layer help separate applications and secure their communications. Common ports include 80 for unsecured HTTP, 443 for secured HTTPS, and 21 for unsecured FTP file transfers.

  • The network layer, using IP addresses, routes traffic between machines on a network. Home networks use DHCP to assign addresses and gateways. Enterprise networks use interior gateway protocols like OSPF, IS-IS and RIP for routing. Exterior protocols like BGP route traffic between large networks.

  • The link layer abstracts differences in network links and includes protocols like Ethernet for wired networks and WiFi for wireless local networks.

  • Physical layers specify the actual transmission medium and modulation of signals, like copper wires, fiber optics or radio frequencies for wireless networks.

So in summary, the transport, network, link and physical layers work together to securely transmit data between applications running on devices connected over a network. Numbered ports and protocols at each layer help facilitate this communication.

  • The person worked at an internet service provider called Erols where they started in support but ended up in system administration.

  • They then worked at MITRE, an organization that does security work like running the CVE system for security alerts. At MITRE they worked on aviation systems, both hardware and software.

  • They majored in computer engineering in college against advice, as they wanted to work on the “whole problem” including both computer science and electrical engineering aspects.

  • Over the past 7 years since building applications, some key things learned include stacks are better and easier to get to market, but also organization design impacts system architecture - the organization resembles the software system built. Technical debt needs to be reduced regularly. Organization design can also drive microservices in unintended ways.

  • They are now interested in and working on topics like crypto, cannabis and nonprofits which they see as having world-changing potential. They see security implementation and evaluation as a major issue for these industries and are interested in solutions to help organizations identify and prioritize key security areas.

  • The passage discusses models in databases and how to properly structure them according to normalization forms like 1NF, 2NF, and 3NF. This helps ensure data is organized, consistent, and avoids redundant data.

  • It provides examples of tables structured according to normalization to represent parts and manufacturers data.

  • SQL is introduced as the dominant language for working with relational databases. Some basics of SQL are explained like CRUD operations and using queries.

  • NoSQL databases are discussed as an alternative to relational databases. They don’t use tables and relations but instead structured data like documents or key-value pairs.

  • Reasons for the rise of NoSQL databases include better developer experience with interfaces resembling code, ability to handle big unstructured data like user activity logs, and ability to scale dynamically with distributed systems and cloud infrastructure.

  • Firebase is used as an example NoSQL database, showing how data could be structured as documents with nested key-value pairs like in JSON. This provides a simpler data model compared to relational tables.

So in summary, it covers relational database modeling concepts, introduces SQL, and discusses the emergence of NoSQL databases as an alternative for certain use cases like big data and improved developer experience.

  • NoSQL databases allow you to store unstructured or changing data without defining a strict schema upfront. This can faster development by allowing you to get an app launched quickly without worrying about schema design initially.

  • However, for tasks like analytics or automated order processing that require structured data, you will eventually need to define a schema to map the unstructured data.

  • The rise of cheaper storage and horizontal scaling enabled by cloud computing made NoSQL databases more feasible. Storing redundant schema information for each item increases storage costs less than it used to.

  • Common NoSQL database types include document stores like MongoDB, graph databases like Neo4j, column stores, and key-value stores.

  • For Google, their massive user behavior data and data science expertise allows them to very accurately predict things like what search results or ads a user will click on, fueling their highly lucrative advertising business model.

  • Their data assets and predictions are constantly improving due to the network effects of such a large user base providing even more training data. Other companies like Facebook also leverage big user behavior data for targeted advertising.

  • Big data helps Amazon stay on top in retail through creating more purchasing habits with buyers, better terms with vendors, and third party sellers. It enhances key profit drivers like product selection, pricing & promotions, supply chain efficiency, and membership programs like Prime.

  • Tesla is collecting huge amounts of data from its vehicles which helps improve self-driving models. This big data advantage may be difficult for others to compete with.

  • Individuals or companies can focus on collecting and labeling valuable customer behavior data they have access to, like shopping data from supermarket customers, to develop their own big data assets.

  • Large companies store historical and unstructured big data in data warehouses and data lakes rather than live production databases. These systems enable easier self-service analytics.

  • Data wrangling involves preparing and standardizing raw data for analysis. Common practices include documentation, version control, and mapping inconsistent data formats.

  • Data science uses big data and hypothesis testing techniques to make economically useful predictions. It requires data scientists, talent in statistics and programming, and clear business goals and data access from product teams.

Here are the key points about how data science interacts with the product pipeline:

  • Data science creates and makes use of “data in motion” rather than just static “data at rest”. This requires continuously incorporating new user data and using it to iteratively update predictions and user experiences in real time.

  • Tools like A/B testing platforms allow data science teams to introduce their own independent variables (tests/experiments) and design experiments to make causal inferences, similar to randomized controlled trials. Companies like run thousands of experiments concurrently.

  • Integrating data scientists into the product team’s iterative workflow helps them understand customer needs/problems better to ask the right questions and frame hypotheses. It also allows breaking big questions into smaller, testable pieces to answer adaptively in sprints.

  • Having data scientists work with “data in motion” from a live product gives them a more realistic experience versus static publicly available data or simulated user data from services. But coordinating real user data access is challenging.

  • Both the product team and data scientists benefit from collaborating through practices like continuous design/delivery to rapidly build, test, and iterate on the product based on data-driven insights.

In summary, data science is most effective when tightly integrated into the product development pipeline to continuously learn from and improve the real user experience through experimentation.

The passage discusses popular applications of data science in business, focusing on forecasting demand and maximizing customer lifetime value (CLV) through customer experience (CX) interventions.

For demand forecasting, the key is starting with an actionable dependent variable tailored to the specific business, like forecasting ingredients for an ice cream shop. Forecasting requires careful experimentation to account for factors like different data availability cadences and discrete business variables like staffing whole numbers of employees.

Maximizing CLV through CX interventions looks at using customer data to send targeted messages, offers, or support to encourage customer engagement and retention in subscription-based businesses. Survival analysis techniques are useful here to model when customers are most likely to churn or cancel and intervene before fully losing the data when they do cancel. The goal is finding the right recipe through testing to extend the customer’s lifetime with the company.

In both cases, the passage emphasizes taking a disciplined, iterative data science approach tailored to the specific business needs and dependent variables involved to deliver actionable insights, rather than one-size-fits-all solutions.

  • Conjoint analysis is a useful tool for optimizing pricing and features in mature product categories where customer preferences are well understood. However, it is not as useful for new, innovative products where customer preferences are unknown.

  • Classification uses machine learning to automatically label images or other data based on training data of labeled examples. It is commonly used for tasks like image recognition. However, determining the right definition or “ground truth” for categories can depend on the specific application and goals.

  • Recommender systems power recommendations for “customers who viewed this also viewed…” They cluster similar products/content but the clusters and dimensions may not have clear human-interpretable meaning. Working with interdisciplinary teams to discuss and label clusters can help make models more useful.

  • To manage big data investments, companies should have a process to identify opportunities across teams, set goals and metrics, and iteratively test hypotheses through experiments linked to OKRs. Key challenges include ensuring access to quality data, developing a culture of experimentation, avoiding inaction when opportunities exist, and acquiring the right talent.

  • The passage discusses cybersecurity and the importance of taking a collaborative, interdisciplinary approach to building a high-functioning security program. It notes that security should be part of the economic calculus when teams choose technologies and solutions.

  • It introduces the concept of DevSecOps, which borrows from the DevOps model to integrate security practices into the product development pipeline in an iterative way.

  • Breaches can happen in any way imaginable, as networked systems are constantly scanned and probed by automated bots looking for vulnerabilities. Attackers have armies of compromised “zombie” computers that can probe infrastructure cheaply.

  • As more activities move online, cyber attacks have grown from a hobby to a major security threat carried out by organized crime and nation-states. Cyber insurance costs are rising sharply as the relative costs of breaches increase.

  • An integrated, collaborative approach that considers security at each stage of development can help mitigate risks compared to a siloed security model that reacts to problems after the fact. Continuous integration of security practices mirrors how quality is built into products through DevOps.

In summary, the passage discusses taking a holistic, interdisciplinary approach to cybersecurity modeled on DevOps principles, as opposed to a reactive, siloed security model. It provides context on the scale of threats and challenges in securing networked systems.

  • Breaches can happen at every level of the “stack of stacks” model, from individual user behavior up to governing entities that establish standards.

  • At the organization level (L9), social engineering attacks target company employees, identifying vulnerabilities in processes/systems to gain unauthorized access to accounts or systems.

  • At the individual level (L8), social engineering also targets end users directly, such as fake Google Doc invite emails containing malicious links. Clicking these can lead to intrusion via malware or stolen credentials.

  • The attack process generally involves 5 steps: 1) identifying a target and vulnerability, 2) intruding by exploiting the vulnerability, 3) implementing/persisting unauthorized access, 4) fulfilling the original malicious intent, possibly moving laterally within systems.

  • User behavior can enable breaches if they click links or open attachments from untrusted sources, allowing intrusion. Server vulnerabilities may also be exploited directly over the internet if not properly secured.

So in summary, breaches can happen at any level due to vulnerabilities in technology, processes, or human behavior - whether through direct attacks or unintended enabling of threats. Social engineering is a common tactic.

In summary:

Breaches can happen in application code through vulnerabilities like overflows and injections, where malicious inputs exploit weaknesses in how the code handles user-provided data. These inputs can allow attackers to access unauthorized data or run unauthorized commands.

Breaches can also happen due to vulnerabilities in third-party libraries, bins, and applications that are incorporated into software. Popular and widely-used open source components are more likely to be discovered and exploited. While obscurity may seem safer, in reality vulnerabilities tend to be similar across software regardless of popularity.

Major vulnerabilities in widely-used third-party code like Log4j illustrate the risks, as they can rapidly impact thousands of applications. Mitigation strategies include keeping deployment pipelines fast and easy to rapidly apply fixes, and maintaining clear visibility into all third-party components used. Vigilant monitoring of software supply chains is also important for spotting and responding to vulnerabilities.

Here are some key ways that networks can impact security:

  • Network architecture and configuration - How the network is set up, segmented, firewall rules etc. can help restrict access and prevent threats from spreading. Poor setup increases exposure.

  • Network traffic inspection - Monitoring network traffic flows allows detection of anomalies that could indicate a compromise or threat. Inspection enables response.

  • Encryption and authentication - Encrypted and authenticated network connections prevent snooping and spoofing that could enable attacks. Proper encryption implementation is important.

  • Firewalls and intrusion detection/prevention - Firewalls block access according to rules, while IDS/IPS systems monitor traffic for known bad patterns or protocol flaws that signify threats. They provide a layer of network-level protection.

  • Remote access - VPNs and other remote access methods need strong authentication and encryption to securely enable remote users without exposing the internal network. Configuration issues can decrease security.

  • Third-party access - Access provided to third parties like vendors increases risk if not properly segmented and monitored. Improper access controls can enable compromises.

  • Physical/wireless security - Issues like inadequate physical access controls or insecure wireless networks increase the risk of threats directly accessing the network from within an organization.

So in summary, network architecture, configuration, traffic management and access controls all impact how easily threats can infiltrate systems or move laterally once on the network. Proper network security practices are important for any organization.

DNS plays an important role in network security by acting as a gatekeeper that determines which devices can access other devices and resources on a network. Some key points:

  • DNS directs traffic by mapping domain names like to IP addresses, determining where internet traffic is routed. This acts as a front gate, controlling which devices can reach internal network resources.

  • By default, most networks are configured to block inbound requests from the public internet to internal devices. DNS serves an important role in this by only allowing outbound requests, not inbound, for additional security.

  • DNS data provides information about domain reputations and behaviors that network admins can use to automate security measures. For example, detecting malware domains or blocking access to known bad IP addresses.

  • DNS providers run security measures like rate limiting login attempts to prevent brute force attacks. Properly configuring DNS access and updating DNS records helps harden systems against intrusion attempts from the public internet.

  • In cloud environments, DNS is integrated with identity & access management systems to facilitate a zero-trust model where access must be explicitly granted rather than assumed on the same network. This limits the impact of any compromised asset.

So in summary, DNS plays a useful role by providing that front gate which helps reduce intrusion attempts on the inside of your network or networks. It controls inbound traffic and provides data to automate security monitoring and response.

Certificates play a key role in security by enabling encrypted and authenticated communication via HTTPS. Specifically:

  • Certificates validate the identity of a website/server and allow the client (browser) to verify it is connecting to the legitimate site, rather than an impersonator.

  • During the TLS/SSL handshake when establishing a HTTPS connection, the server presents its certificate which the client can check against a list of certificate authorities it trusts. This confirms the server’s identity.

  • If a site does not have a valid certificate or the certificate cannot be verified, browsers will display warnings to notify users that the identity of the site cannot be confirmed.

In terms of website breaches, the key factors discussed are:

  • Ensuring the underlying software (e.g. PHP, WordPress) is regularly updated to patch vulnerabilities. The larger developer community and investments influence this.

  • Proper configuration and management of hosting/infrastructure by companies like WP Engine to maintain security practices and apply patches/updates.

  • Other layers like DNS, certificates, firewalls must also be properly configured and maintained to prevent compromises higher in the technology stack from impacting the website.

The main roles of certificates are confirming server identity via TLS/SSL and preventing man-in-the-middle attacks, while regular updates to software and diligent host/infrastructure management help prevent vulnerabilities from being exploited.

Here are the key points about attackers and what they want according to the passage:

  • Cybercrime is a major motivation as online crime and money is increasingly moved online. Cybercrime ranges from individual hackers to state-sponsored espionage operations.

  • State-sponsored attackers like Russia, China, Iran and North Korea have substantial cyber operations as it’s seen as a form of asymmetric warfare.

  • There are also ideological hacker groups like Anonymous that engage in cause-based hacking to promote certain political goals.

  • There is overlap between criminal and state-sponsored attackers, as states will commission criminal hackers to conduct attacks while maintaining plausible deniability.

  • Examples of hackers groups with state affiliations are Cozy Bear (Russia), Lazarus Group (North Korea), and Double Dragon (China).

  • In general, attackers are motivated by money from criminal activities like cybercrime, exploitation of vulnerabilities for sales in “zero day” markets, or political goals in the case of state-sponsored and ideological hackers. Their goal is to conduct hacking operations for various motivations ranging from financial gain to cyber espionage and warfare.

Here are the key points about how companies secure their digital assets and customers:

  • Companies have to defend against vulnerabilities at every layer of the technology stack, from hardware and network infrastructure to applications, data, and user accounts. Attackers only need to find a single vulnerability to exploit, while defenders have to address vulnerabilities across the whole stack.

  • Common approaches for companies include using firewalls, securing device software and operating systems, implementing tools for access control, monitoring systems for anomalies or attacks, and running bug bounty programs.

  • Companies have to prioritize security investments since it’s impossible to address every potential issue. The risks of a breach are high, so managing security is nerve-wracking.

  • Relying solely on third-party security products is flawed since one size does not fit all. Companies need expertise but also have to adapt solutions to their specific environments and use judgment over time based on observations of what works and doesn’t work.

  • A coordinated, team-wide approach is ideal, involving security experts, developers, IT operations, and making security part of company culture. Continuous improvement is also important based on learning from experiences.

So in summary, companies take a layered, adaptive approach involving both commercial tools and internal expertise/processes to defend the range of vulnerabilities, prioritizing the most critical risks. Judgment and learning over time are also key aspects of effective security.

Here are the key points about how companies can protect themselves at the level of individual product teams:

  • Product teams have a lot on their plate already and security is not usually their top priority. They need clear guidance and tools to help incorporate security into their work.

  • A centralized security program alone may struggle to ensure alignment with product teams. Too much decentralization can miss larger security threats.

  • The best approach embeds security expertise directly into product teams through contributors, while also maintaining centralized capabilities for common practices, tools, and guidelines.

  • Tools like IAM and secrets management are complex but essential - a central team of experts can enable self-service for product teams through shared infrastructure, avoiding duplication of effort.

  • Product teams introducing known vulnerabilities unnecessarily wastes resources - the goal is for security experts to help teams avoid vulnerabilities from the start through guidance and infrastructure.

So in summary, effective security at the product team level balances centralized expertise, tools and standards with direct support embedded within interdisciplinary teams to drive security as an inherent part of the product development process.

Here are some key ways companies can protect themselves at the application, presentation, and session layers (OSI layers 7, 6, and 5):

  • Scan applications for vulnerabilities and conduct penetration testing to find issues before attackers. This is often done through continuous integration/deployment pipelines.

  • Implement zero-trust authentication so all users and systems must authenticate even internally. Encrypt sensitive data so it’s protected if accessed.

  • Minimize sensitive data footprint by only storing necessary customer information. Check logs, configs, code for accidental leaks of sensitive data.

  • Conduct regular backups in case of ransomware or data theft attacks. Maintain ability to wipe and restore from backups.

  • Leverage DNS for protection, e.g. using secure DNS services that block connections to known malicious domains. Watch for DNS tunneling.

  • Make applications resilient through technologies like Kubernetes that can withstand individual infrastructure failures or DDoS attacks and recover lost resources.

  • Protect communications and data exchange through measures like HTTPS, HTTPS certificate validation, TLS encryption at the presentation and session layers.

The focus is on finding and fixing vulnerabilities, access control, data protection and classification, backups, DNS security, and making applications resilient through technologies like containers.

Companies protect themselves at the network (layer 3) and transport (layer 4) layers by implementing firewalls and network access control to block most inbound traffic and allow most outbound traffic. This helps secure their internal network infrastructure.

For public-facing applications, companies use software-defined networking and identity and access management systems at these layers to automatically control which machines can communicate over the network and enforce access policies.

At the data link (layer 2) and physical (layer 1) layers, security is more limited as these components are interchangeable hardware. Some national restrictions exist, such as limiting certain Chinese networking equipment suppliers for security reasons.

Security professionals within companies work to defend against attacks through tasks like vulnerability research, implementing security best practices and tools for end users, and penetration testing. Tools like Metasploit help automate security testing and disclosure of vulnerabilities to vendors to help both white hat and black hat hackers. Responsible disclosure practices have evolved over time.

Overall, the dynamic between hackers and security has been tense as both aim to outwit each other, but tools like Metasploit and guidelines have helped professionalize the field while also increasing defenses for companies. Case studies of attacks like Stuxnet further illustrate how these concepts play out in real-world incidents.

  • The Zeus malware, allegedly created by Evgeniy Mikhailovich Bogachev, was adapted to exploit vulnerabilities and criminal opportunities profitably rather than for a focused goal like Stuxnet.

  • Zeus spread initially through phishing emails with malicious PDFs or other files that exploited software vulnerabilities to covertly install the trojan on victim’s devices.

  • Once installed, Zeus would steal login credentials, banking information, and remotely control the user’s browser to facilitate bank fraud and money transfers without arousing suspicion.

  • This allowed large scale theft directly from individual bank accounts starting in the late 2000s, making investigations difficult as transfers appeared to originate from victims.

  • Over time, the criminal enterprise evolved and expanded by licensing the Zeus software and leading a network of money mules to help launder stolen funds.

  • Millions of victims, mostly households, had their accounts drained as a result of the widespread and persistently installing Zeus trojan adaptations. It created reliable cybercriminal infrastructure through widespread device intrusion and control.

Here are the key points about ransomware from the summary:

  • Ransomware describes an attack where the intention is extortion related to impairing a company’s operations by encrypting their data and demanding a ransom to unencrypt it.

  • The attack starts with a “loader” trojan virus that infiltrates the system. Once installed, it launches the ransomware payload which encrypts all the user/company’s data and leaves a ransom note with instructions.

  • It then seeks to spread laterally within the company’s network. This makes it difficult for the victim to recover without paying the ransom, as restoring from backups may not help if encrypted data is also stored on file shares across multiple machines.

Ransomware is profitable for attackers because:

  • It directly enables extortion by encrypting important/all of a victim’s data and holding it hostage until ransom is paid.

  • With the rise of cryptocurrency, ransoms can be collected anonymously, making it hard for law enforcement to track payments.

  • Many victims feel compelled to pay given the potential damages from lost access to critical data and systems. This has made ransomware a low-risk, high-reward criminal business model.

So in summary, ransomware preys on the vulnerability of unpatched systems and human impulse to pay to recover access, making it a very lucrative attack for cybercriminals.

  • Dave was formerly a network engineer who became interested in security out of a desire to better understand networks from a security perspective, given the silos between network and security teams. He also enjoys the dynamic nature of security work.

  • In the past 10 years we’ve learned that criminal hacking groups operate without silos or borders, making them more agile than traditional companies. We’ve also learned that hard security perimeters are less effective than focusing on internal protections like zero trust.

  • Going forward, visibility will be important as infrastructure moves to the cloud. Security needs to catch up as organizations’ structures change. More durable security solutions are still needed that don’t require frequent replacement as tactics evolve.

  • Dave sees protective DNS as a scalable approach for continuous detection of threats like the Log4j vulnerabilities. At his current company Hyas, they are pursuing similar visibility and protection solutions through DNS.

Three key questions were asked of Dave regarding his background, lessons learned in security, and where the field is headed. The summary focuses on the main points conveyed in his responses.

This passage summarizes key differences between traditional 20th century marketing approaches and newer organic growth tactics used by many 21st century tech companies:

  • Traditional marketing focused on high fixed costs for production/distribution but low costs for the core product technology. Tech companies invest heavily in proprietary core technologies.

  • Traditional products had high variable costs like production, shipping, spoilage. Tech products have mostly fixed development costs and low marginal costs.

  • Traditional products offered low differentiation but predictable sales based on historical data. Tech products can disrupt markets and change buyer behavior unpredictably.

  • Traditional marketing relied on long-term planning and the “Four P’s” tactics in roughly equal measure. Tech companies emphasize unpaid promotion and viral growth over traditional paid advertising approaches.

Overall it describes how traditional marketing assumed stable economics and predictable buyers, while tech companies face rapidly changing markets and aim to scale through unpaid, organic growth tactics rather than long-term sales forecasts and advertising budgets. This unconventional approach has allowed many tech firms to achieve “spectacular valuations” without conventional marketing investments.

  • Traditional marketing focuses on careful long-term planning of products, production, promotion, etc. aimed at incremental improvements. But this approach does not work well for digital products.

  • Growth hacking is similar to marketing but adapted for the agile, interdisciplinary approach of tech companies. It focuses on testing hypotheses through experiments rather than top-down strategies.

  • In tech, product managers have more responsibility for product success than traditional marketing departments. Marketing plays a supporting role in helping scale successful products.

  • Traditional R&D focuses mainly on technology, not customer needs or business models. Innovation-friendly approaches invest more in learning customer jobs-to-be-done and testing new solutions and models.

  • Successful digital products rely more on designing for the customer experience through experimentation than on careful production and promotion planning. The costs of going from 0 to 1 are high, so hypothesis-driven experimentation is important.

  • Traditional functions like production, support, and promotion optimized local efficiency over holistic customer outcomes. Innovation approaches measure success based on customer relationships and economics rather than internal metrics.

  • Promotion is typically done separately by individual product teams and measured by things like sales numbers, whereas digital marketing allows for more experimentation and direct measurement.

  • Strategic marketing activities are often not directly measurable.

  • While branding and media are sometimes centralized, promotion is still done separately by each product team as part of defining their success.

  • The example company HinH provides HVAC services and sees opportunities in areas like budget predictability, uptime reliability, and total cost reduction.

  • The startup Enable Quiz provides technical skills assessment tools for hiring. They define product-market fit as users being very disappointed if they could no longer use the product.

  • Enable Quiz sees opportunities in screening candidates for HR managers. Their goal is to scale, extend, and cascade their initial product-market fit by mapping out the user experience and acquisition funnel. Direct measurement will help them test new segments and features.

  • Product-market fit is ongoing work and doesn’t last permanently - companies must continuously improve and maintain fit over time with growth. The customer experience map is a tool to help do this.

  • The passage discusses operationalizing product-market fit for growth hacking and revenue operations (RevOps) through a hypothesis-driven approach.

  • It introduces the Growth Hacking Canvas as a tool to answer questions about what the product means to customers and how to amplify that meaning.

  • The right side of the canvas focuses on customer segments and value propositions to understand the brand’s meaning to customers.

  • The left side focuses on ways to amplify customer involvement with the brand through promotional executions, relevant assets, and infrastructure capabilities.

  • Subsequent sections will look at understanding what the product means to customers through branding, associations, and the visceral layer of user cognition. Branding creates meanings and resonances that influence customer behaviors.

  • While branding is often associated with large consumer brands, it also matters for B2B products by understanding when and how the product matters to customers amid all their other priorities and associations.

So in summary, it introduces the Growth Hacking Canvas as a tool to operationalize product-market fit understanding for targeted growth initiatives, focusing on branding and customer meaning and experiences.

Here are the key points about creating durable customer relationships through designing customer experiences (CX):

  • Nir Eyal’s “Hook” framework outlines how users go from a Trigger to an Action, then receive a Variable Reward and invest further. The first step is finding triggers to prompt the intended action.

  • Triggers can be external (notifications) or internal (feelings/thoughts). Understanding activity cadence is important - some products have high frequency triggers, others low.

  • The Action is the minimum interaction required, like a search or scrolling social media. Products should minimize effort required for the action to occur.

  • onboarding and acquisition tasks like sign-ups are often neglected but provide opportunities to reduce required actions through usability testing.

  • Providing a Variable Reward keeps users engaged - it needs to be partially unpredictable to maintain interest. Testing different rewards helps engage customers.

  • Investment means users expend some amount of effort/data/social buy-in that locks them into the product more deeply over time through network effects or data collection.

The key is understanding customer triggers, minimizing actions, providing unexpected rewards, and creating investment to develop durable relationships through continued usage and retention. Testing is important at each step of the customer experience.

  • Action should be minimized and rewards maximized at critical points in the user journey to reduce churn. More action is not necessarily better engagement.

  • Rewards come in the form of variable rewards, social affirmation/rewards of the tribe, excitement of discovery/rewards of the hunt, and mastery/rewards of the self. Consistency in minimizing action for rewards is important.

  • Users invest in a product by setting themselves up for the next trigger, storing value like social status, accumulating consistency to validate actions. This increases their long-term investment.

  • Churn is reduced by focusing on the key driver of growth - paid, viral, or stickiness. Analyze churned vs retained users to find “smoking gun” factors strongly associated with churn through retrospective case control studies. Discovery interviews may also help identify less obvious causes. The goal is to reduce churn reasons material to the business model.

  • When acquiring the wrong customers, RCC analysis may show the key variable distinguishing engaged vs disengaged users is something like gender/age segments (e.g. moms for a parenting app). Discovery interviews can help uncover these customer attributes.

  • Poor onboarding leads to low engagement visible on a customer journey map. RCCs can compare onboarders vs non-onboarders to find predictors, and interviews can provide insights. For example, company size may predict onboarding for an HR tool.

  • When customers don’t achieve outcomes, hard questions need asking via surveys or interviews since outcomes aren’t directly observable. Reasons can be an inadequate product, wrong customer segments, incomplete understanding of customer goals. Addressing this requires courage and patience.

The key points are that RCC analysis combined with qualitative research can help diagnose reasons for churn related to the acquisition, onboarding, engagement and outcome stages of the customer experience/journey. Insights inform experiments to improve customer retention.

  • Enterprise/B2B product acquisition often happens through large contracts which then requires onboarding different user groups. The pains and gains of implementing such systems are often offset (e.g. more work for salespeople but benefits for downstream processes).

  • Persona hypotheses, job-to-be-done hypotheses, and demand hypotheses are still important frameworks even for complex enterprise products. Orrery boards can help unpack and relate these hypotheses to better understand desired outcomes.

  • Churn can occur if the wrong customer segments are acquired. Thoroughly testing acquisition channels and segments across the customer journey can help identify underperforming sources early on.

  • If retention behaviors are not as expected, it’s important to understand the assumptions about what retention is needed based on the business model (e.g. paid models require sufficient revenue per customer).

  • Dropbox originally relied on paid search but costs were too high, so they leveraged their natural viral growth through file sharing and referrals which better fit their freemium model goals. Thoroughly understanding growth engines is important for acquisition and retention strategies.

  • In 2009, Dropbox abandoned paid search and by April 2010 had acquired 4 million users through organic acquisition channels like referral programs, shares, and word of mouth. 35% of users came from the referral program, 20% from shares, and the rest from general word of mouth.

  • This business model focused on virality started working well for Dropbox. Paired with strategic pricing decisions, the organic growth approach powered the business. The referral program and easy sharing options helped Dropbox scale through word-of-mouth and social spreading organically.

  • The writer purchased a Flip N Slide Bucket Lid Mouse Trap based on recommendations from YouTube channel Shawn Woods, who tests various rodent traps. Woods has an affiliate partnership with the trap maker RinneTraps.

  • This shows how a small startup like RinneTraps can reach customers through influencer marketing at low cost, competing with larger established brands like Victor. Affiliate marketing allows them to connect with the right third parties.

  • Search engine optimization is also important for content and website visibility. Factors like backlinks, user engagement, and whether users find answers on a site impact search rankings.

  • Social media allows sharing content and getting feedback, forming community around a brand. Some companies work with influencers to produce custom social media content.

-Traditional big agency processes are less effective now with many channels and stakeholders. Some agencies use workshops to brainstorm diverse small executions that work better for social media’s more organic style. Third party developer programs also help scale products.

The passage discusses different paid channels that can be used to scale product-market fit, such as online ads on platforms like Google, Facebook, LinkedIn, Instagram and YouTube. It emphasizes the importance of testing hypotheses through paid ads and optimizing for key metrics like customer lifetime value (CLV) versus cost per acquisition (CPA).

Specific examples are given of how a company called Enable Quiz could run paid search ads on Google targeting technical recruiter job searches. Landing pages and email acquisition funnels are described. The importance of A/B testing ads, emails and calls-to-action is highlighted to find an acquisition strategy that is profitable.

Four questions are outlined to help decide where to run ads: 1) defining the target persona, 2) where the persona currently spends time online, 3) whether the brand fits on the target site, and 4) determining the maximum acceptable CPA given the business model. Lookalike audiences on platforms like Facebook and LinkedIn are also recommended to amplify successful audiences. In summary, the passage provides advice and examples for how to leverage paid channels like online ads to test hypotheses and scale product-market fit in a measurable way.

Based on the information provided,

The user is discussing growth hacking strategies and opportunities to better understand website visitors in order to improve advertising effectiveness and economics. Specifically:

  • Analyzing search keywords to glean user intent and willingness to pay, like comparing generic “digital camera” to a specific model.

  • Leveraging platforms like Google/DoubleClick and YouTube to target ads to individuals based on their online activity and inferences about them.

  • Using social media platforms like LinkedIn to target ads based on first-party data shared by users, like job titles or companies.

  • Considering offline events like trade shows to directly engage potential customers.

In terms of assets to cultivate, the user recommends focusing on brand lexicon/messaging, existing high-traffic content, and promotional expertise either through hiring or experimentation. The overall goal seems to be optimizing the customer experience across different channels to drive engagement and conversions.

So in summary, the user is advising taking a data-driven approach to understanding site visitors and leveraging different platforms to personally target ads, with the aim of improving marketing results through behavioral design and consistent brand messaging. The focus appears to be on actionable growth hacking strategies.

  • Hypothesis-driven development (HDD) is a approach that can help generalist digital professionals prioritize their skills development and focus their learning on what will be most useful.

  • It’s recommended to start applying skills from the top of the “HDD skills stack” diagram - things like experimentation, analytics, and product management - rather than focusing first on basic technical skills. Starting higher up keeps the learning job-relevant.

  • Side projects are suggested as a way to get hands-on practice applying HDD concepts in a low-stakes way. Projects should have a clear learning goal, like going from design to code or vice versa.

  • Creating a portfolio entry documenting the side project’s methods, outcomes and lessons learned helps maintain focus on the intended learning objectives rather than getting too bogged down in other aspects.

  • When trying to introduce HDD to a team, the hardest part is creating interdisciplinary focus on user outcomes. Teams need help framing experiments and initiatives around shared goals to facilitate self-organization and collaboration across specialties.

  • The book discusses how to apply the principles of Hypothesis-Driven Development (HDD) at the business/organizational level through techniques like the Business Model Canvas and Corporate Innovation Canvas.

  • The Business Model Canvas allows teams to define their current or hypothetical product/market fit using concepts like customer segments and value propositions. This helps align stakeholders on the existing business model design.

  • For larger companies, the Corporate Innovation Canvas provides a framework to define important customer segments/jobs-to-be-done, disruption catalysts, existing assets, and innovation goals that can be broken down into specific initiatives.

  • The key is having clear definitions of success that cascade from the overall company down to business units/teams/individuals. Outcomes should inform relevance from the bottom up.

  • The author recommends starting small by picking practices like agile team charters, business model sketching, or innovation portfolio development that can help translate HDD principles to an organization over time. Showing results is more important than just telling people about the approach.

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About Matheus Puppe