Glossary / metrics

Cohort Analysis

metrics

Quick Definition

Cohort analysis groups customers by acquisition period (e.g., Jan 2024 signups) to track retention, revenue, and behavior over time. Shows if your product is getting better or worse at retaining customers.

Detailed Explanation

Cohort analysis is THE most important retention metric. Group customers by when they signed up (cohorts), then track what % stay active month-by-month. Example: Jan 2024 cohort—100 customers signed up. Month 1: 80 active (80% retention). Month 2: 60 active (60% retention). Month 3: 55 active (55% retention). Month 6: 50 active (50% retention). Plot this for every monthly cohort side-by-side to see trends: Are newer cohorts retaining better (product improving)? Or worse (product-market fit declining)? Ideal cohort curve: Steep drop month 1-2 (onboarding friction), then flattens out (loyal users stay). Bad cohort curve: Continuous decline, never flattens (no loyal user base). Segment cohorts by: Acquisition channel (organic vs paid—organic typically retains better), customer type (enterprise vs SMB), pricing plan (annual vs monthly). Use cohort analysis to: Measure product improvements (did new onboarding increase Month 2 retention?), predict LTV, identify best acquisition channels, justify pricing changes.

Real-World Examples

Spotify

Tracks cohorts religiously. Found users who created playlists in Month 1 had 2x higher Month 12 retention. Changed onboarding to push playlist creation—retention jumped 30%.

SaaS with good cohorts

Jan cohort: 100 users → 80 (Month 1) → 70 (M2) → 65 (M3) → 60 (M6) → 55 (M12). Flattens at 55%. Clear loyal user base. Can predict LTV accurately.

SaaS with bad cohorts

Every cohort drops from 100 → 50 → 25 → 10 → 5 by Month 6. Never flattens. No PMF. Shut down despite raising funding.

Why It Matters for Your Startup

Without cohort analysis, vanity metrics hide problems. You might add 1,000 users/month but lose 1,200 (net negative). Cohort analysis reveals true retention, lets you calculate accurate LTV, shows if product changes improve or hurt retention.

Common Mistakes

  • Only looking at total users (hides churn—1M users might be churning 100K/month)
  • Not segmenting cohorts (organic vs paid have different retention profiles)
  • Short time horizon (need 12+ months to see true retention curves)
  • Not acting on cohort insights (seeing Month 2 drop but not fixing onboarding)
  • Comparing first cohorts to later (early adopters always have different behavior)

Frequently Asked Questions

What retention % should I aim for?

Month 2: >40% is good signal. Month 12: >30-40% is excellent (means loyal user base). If Month 6 retention is <20%, likely no PMF—users don't find value.

How often should I check cohort analysis?

Monthly for high-growth startups. Quarterly for mature companies. Need at least 3-6 months of data before cohort curves stabilize and show patterns.

What if my cohorts are getting worse over time?

Red flag. Newer customers retaining worse than old = product quality declining, wrong target market, or competition improved. Must investigate and fix urgently.

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Cohort Analysis - Definition, Examples & Formula | StartupIdeasDB Glossary | startupideasdb.com