Funnel & Cohort Analysis

Funnel analysis

Sequence of step user phải hoàn thành để đạt outcome. Mỗi step có conversion rate. Tổng conversion = product of step CR.

E-commerce checkout funnel

Funnel debugging

• Identify lowest CR step — biggest opportunity.
• Segment by device, region, source — find disproportionate drop.
• Watch session replay (Hotjar, Fullstory) cho qualitative signal.
• Run experiment trên 1 step at a time.

Cohort analysis

Group user theo time of first action, track behavior over time. Reveal retention trends mà aggregate metric hide.

Retention cohort table

Signup week    | D1  | D7  | D30 | D90
Week 1 (Jan)   | 55% | 25% | 18% | 12%
Week 2 (Jan)   | 58% | 28% | 20% | 14%
Week 3 (Jan)   | 60% | 30% | 22% | —

Retention curve shape

• Smile curve — drop rồi rebound → PMF tốt (Facebook).
• Plateau curve — flatten sau drop → user habit formed.
• Cliff curve — drop rồi tiếp tục → leaky bucket, fix activation/onboarding.

Tools

• Mixpanel, Amplitude — funnel + cohort built-in.
• GA4 — free, but UI clunky.
• SQL custom cho deeper analysis.

Common pitfalls

• Look at aggregate retention → miss cohort drift.
• Funnel with 10 step — segment quá nhỏ ở cuối.
• Confuse retention với engagement.
• Optimize one funnel step → metric tổng giảm (Goodhart).