The three measurement skills a product manager uses weekly: reading where people fall out, reading whether they come back, and knowing when a test result is real. Every formula here is defined in this topic and linked from everywhere else.
| # | Lesson | The question it answers | |
|---|---|---|---|
| 01 | Funnel Mechanics | How does loss compound across stages, and where is the leverage? | |
| 02 | Defining a Conversion | What counts, over what denominator, in what window? | |
| 03 | What Retention Means | Which of the three common definitions are you using? | |
| 04 | Building a Cohort Table | How do you build the one chart that tells the truth about a product? | |
| 05 | The Curve and the Flattening | Does it flatten, and why does that decide whether you have a business? | |
| 06 | A/B Testing and When It Lies | Power, duration, peeking, novelty: when is the result not real? | |
| 07 | When You Cannot A/B Test | Holdouts, switchbacks, before and after: what works at low traffic? | |
| 08 | Churn: Logo and Revenue | Why do these move in opposite directions? | |
| 09 | Acquisition Cost, Blended and Paid | What belongs in the numerator, and why is blended misleading? | |
| 10 | Attribution | First touch, last touch, multi touch: in what way is each wrong? | |
| 11 | Deciding With Ambiguous Data | How do you write a decision memo when the data does not settle it? | |
| 12 | Worked: A Funnel Diagnosed | One real funnel, from symptom to cause to fix |