Cohort analysis

Grouping users by when they joined and following each group over time.

Example

January signups retain at 40% by month three; April signups at 62% — the product got better.

Aggregate numbers hide everything interesting. Cohorts are how you tell real improvement from a growing pile of new signups masking churn.

Retention — The share of customers still active after a given period. The inverse of churn, and usually the more useful way round.
Churn — The rate at which customers or revenue leave over a period.
Conversion rate — The percentage completing a step out of those who started it.

Funnels and conversion — Find the biggest leak, not the easiest one. Most founders optimise the top of the funnel while losing 90% at activation. (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)
What product-market fit actually is — Not a score and not a moment. Retention, unprompted return and how hard people fight to keep using it. (12 min)