North-star metric, funnel metrics and guardrails for Meta's Messenger Kids app

You are the product manager for Messenger Kids, Meta's messaging and video-calling app for children. How would you define and measure the app's success? Name the metric you would treat as the north star, the supporting metrics you would track, and the guardrails that keep the product healthy. Assume the publicly known design: the app is meant for children under 13, a parent sets up the child's account, and the parent approves every contact the child can talk to. ```hint Two users, one account A child uses the app, but a parent decides whether it exists at all. Work out what success means for each of them, and what success should never mean for a product built for children, before you choose a metric. ``` ### Clarifying Questions - Is the app at an early stage, where adoption by families is the priority, or mature, where sustaining healthy use matters more? - Is success judged for the app alone, or also by what it does for Meta, such as parents' trust and the engagement of adult relatives the child talks to? - Should the metrics treat all supported ages together, or separately for younger and older children whose usage differs? - What limits do children's privacy rules place on the data we can log and analyze for measurement? ### What a Strong Answer Covers - A product goal that serves the child, the parent and the approved contacts, tied to Meta's mission - A north-star metric that captures real connection between a child and approved contacts rather than raw opens or time spent, with a justified time window - Supporting metrics across the family funnel: parent setup, contact approval, first conversation, habitual use and retention - Safety, wellbeing and parent-trust guardrails, including why maximizing time spent is the wrong goal for children - A clear priority among the metrics, and awareness of the privacy limits on measuring children's behavior ### Follow-up Questions - Your north-star metric is rising, but more parents are deleting their children's accounts. How do you investigate? - How would you tell whether the app makes children's relationships with family better, not just more frequent? - How would you evaluate a proposed feature that lets children connect with classmates without a parent approving each contact?