What to measure at each stage and what to ignore, activation and retention, cohort analysis, north star metrics, and how to tell a real signal from a number that only moves because you looked at it.
Lessons
What to measure, and what to ignore — Different stages need different numbers. Measuring everything is the same as measuring nothing. (12 min)
Activation and retention — The two numbers that predict whether a company works. Acquisition can be bought; these cannot. (12 min)
Cohort analysis — Group users by when they joined and follow each group. It is the only way to tell real improvement from a growing pile of signups. (12 min)
The north star metric — One number that only improves when customers genuinely benefit. Choosing it badly points the whole company at the wrong thing. (10 min)