Duolingo · Metrics · Mid · 45 to 60 minutes

Where should Duolingo find its next DAU growth?

Duolingo is a mobile app and website that helps people learn languages through short interactive lessons. Answer this product management case and get it graded line by line against a weighted rubric.

metric decomposition
strategic prioritization
experimentation
product judgment
stakeholder alignment

The situation

It is mid 2018, and Duolingo leadership asks you, the PM for learner engagement, for a plan to restart daily active user growth. The app still attracts plenty of new users through organic channels, but DAU growth has slowed, and investors want a clearer path to sustained growth and monetization. The team suspects there may be a leaky bucket problem: many people try the product, but too few build a durable daily habit. Duolingo already has some game-like elements, such as progression, streaks, and achievements, but the team has not aligned on which user behaviors matter most or which metric should guide product decisions. Assume a simplified model where DAU is driven by new users, currently active users, reactivated users, and resurrected users, with churn happening across several inactivity stages. You need to recommend how to diagnose the slowdown, which metric or transition rate should become the main focus, and what product bets to test first, without harming the learning experience.

What to produce

Write a 1 to 2 page product strategy memo.

Your answer must

Name one primary goal metric for the next 12 months and 3 supporting or guardrail metrics, with a brief reason for each.
Show a simple metric tree or state model that explains how DAU changes over time and where the main leaks might be.
Choose one growth focus area to prioritize first, such as acquisition, current user retention, reactivation, or resurrection, and justify why it is the highest leverage now.
Propose 3 specific analyses or product experiments, each with a hypothesis, target user segment, and success metric.
Explain the main risks and tradeoffs, including how you will protect learning quality and avoid overstimulating users just to lift activity.
State what evidence you would want in the next 8 to 12 weeks to confirm or change your recommendation.

Constraints

Acquisition is already largely organic, so do not rely on a major new paid marketing budget.
Your scope is learner engagement, not pricing changes or a major curriculum rebuild.
Any messaging based tactic must protect long term channel health and cannot assume simply sending more push notifications or emails by default.

Format

Use clear section headings for goal, metric model, recommendation, experiments, and risks. A small table is welcome.

How Duolingo actually played it

A second reading of the same turnaround, focused on the shift from acquisition to retention and the creation of a dedicated retention team. It lists the churn and streak numbers that moved.

Move focus to retention when growth slows
Give a retention goal its own team
Track share of users with long streaks as a health signal

Built from Breaking Down Duolingo's Growth Model: How they Achieved 450% User Growth by Marisha Lakhiani.