The Duolingo Growth Framework: Finding Your One Metric That Matters

Learn how to build a retention-segmentation model, run sensitivity analysis to find the highest-impact metric, and design concrete product levers around it — using Duolingo's 4.5x DAU growth turnaround as the working example.

3 sections · 7 lessons

Course outline

Why Copying Mechanics Fails

  1. The Moves-Counter Mistake: Why Context Matters When Borrowing Features
  2. The Referral Program That Missed Its Target Audience

Finding the One Metric That Matters

  1. Segmenting Retention: CURR, NURR, RURR, and SURR
  2. Sensitivity Analysis: How Duolingo Found Its North Star Metric

Turning a Metric Into Product Levers

  1. League-Based Leaderboards: Matching by Engagement, Not Friendship
  2. Protecting the Notification Channel Instead of Just Sending More
  3. Designing Around the 10-Day Streak Threshold

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