A language-learning app has 30 lakh monthly active users and makes money from a subscription. The growth team reports daily active users; the content team reports lessons completed; finance reports subscription revenue. The CEO says the teams are optimising for different things and asks you to fix the metrics.
Propose one north-star metric, the input metrics beneath it that teams can own, and the guardrail metrics that would catch the north star being gamed. Explain your choices.
100 points, 60% to pass.
The value delivered is learning that sticks, so the north star should approximate it — e.g. weekly learners who complete a meaningful amount of practice (a threshold, not raw lessons), or learners retained for several consecutive weeks. DAU rewards notifications and streak tricks; lessons completed rewards making lessons shorter; revenue lags and can be bought with discounts. Inputs: new learner activation, week-2 retention, practice depth, subscription conversion. Guardrails: lesson difficulty or assessment scores (to stop lessons being made trivially easy), notification opt-out and uninstall rates, refund rate.