Facebook Product Sense: Building a Signal for How Happy Users Feel

You are a product manager at Facebook. Design a feature that measures how happy Facebook's users are. Explain what you take "happiness" to mean, why Facebook would want to measure it, how the feature would gather the signal from users, and how you would know the resulting measure is trustworthy and worth acting on. ```hint Decide which happiness you mean Being satisfied with time spent on Facebook and being happy in life are different targets, and they need different signals. Settle which one the feature measures, and who will see the result, before you pick signals. ``` ### Clarifying Questions - Should the feature capture satisfaction with the Facebook experience itself, a person's overall well-being, or how Facebook use affects that well-being? - Who uses the measurement: internal teams making ranking and product decisions, the users themselves, or both? - Is a per-person score needed, or is an aggregate across groups of users enough for the intended use? - Which data is off-limits, for example private messages, photos or any inference about someone's emotional state, given privacy law in different regions? ### What a Strong Answer Covers - A working definition of happiness for this feature and a clear reason Facebook wants to measure it, kept distinct from engagement - A concrete design for collecting the signal, weighing direct self-report against behavioral signals and keeping the burden on users low - How raw signals become a validated measure, including response bias, cultural differences in how people rate, and checks that it tracks real happiness - Privacy, consent and ethical limits on sensing how people feel - How the measure feeds product decisions, how the feature's own success is judged, and the risk of teams gaming the number ### Follow-up Questions - After a ranking change, the happiness measure rises while time spent on Facebook falls. What do you tell leadership, and which signal do you trust? - How would you show that the measure reflects how people feel rather than how much they post or react? - Would you show users their own score? What could go wrong if you did?