Video · ~20 min

How To Improve Cohort Retention

David Lieb · Y Combinator Startup School Free Beginner

YC's David Lieb walks through cohort retention: watching each week's new users and asking how many actually come back. For a very early founder that framing answers the real question, because it shows you can read retention off a handful of early cohorts long before you have scale. Treat it as a starting point for how to look at your first users, not a benchmark you must hit on day one.

  • Cohort retention tracks the fraction of new signups who keep coming back, which you can measure even with small early numbers.
  • A retention curve that flattens (rather than falling to zero) is the early signal of real product-market fit worth chasing.
  • Improving onboarding and targeting the right users beats pouring more people into the top of a leaky funnel.
Open on ycombinator.com ↗

It answers 2 questions

  1. How do I actually measure whether a launch worked, beyond the vanity upvotes and traffic spike?
  2. How soon after signup should I even worry about retention versus just getting more users in the door?

Read with it

  1. The nuanced counterweight: PMF isn't a single binary moment, it can be lost, and 'market' is doing more work than founders... a16z.com Article · ~20 min read 12 Things About Product-Market Fit Andreessen Horowitz (a16z)
  2. The reference primer on the metrics and market-sizing logic investors use, including bottom-up market sizing that keeps... a16z Article · ~15 min read 16 Startup Metrics Andreessen Horowitz (a16z)
  3. The origin text for the modern MVP and validated-learning vocabulary every founder now uses. Read it for the mental model that... theleanstartup.com Book · ~330 pages The Lean Startup Eric Ries
  4. The definitive talk that reframes launching from a one-shot event into a repeatable tactic, exactly this category's thesis. YC... YC Startup Library Video · ~25 min How to Launch (Again and Again) Kat Manalac (Y Combinator)
  5. When there is no category report to point at, you have to build the number yourself, and this is the essay that teaches you... Andreessen Horowitz Essay · ~20 min read 16 More Startup Metrics Anu Hariharan, Frank Chen, Jeff Jordan
  6. PostHog gives you product analytics and session replay in one place, so you can see both what people did (events, funnels) and... posthog.com Tool PostHog PostHog
eChai Partner Brands The partnership →