Facebook Birthday Reminders: North-Star Metric, Funnel Metrics and Guardrails

You own birthday notifications at Facebook: the alerts that tell a person a friend's birthday is today and invite them to send a wish. Define how you would measure whether this feature is successful. ```hint Two people share one moment A birthday reminder serves both the friend who receives the alert and the person celebrating. Decide what a good outcome looks like for each before choosing a north-star metric, and ask how much of the activity the reminder actually causes. ``` ### Clarifying Questions - Does the scope cover only the birthday alert itself, or also where the wish lands, such as a post on the friend's profile versus a private message? - Are we judging the feature as it exists today, or deciding whether a new version of it should launch? - Is the aim stronger relationships between friends, more overall activity on Facebook, or both? ### What a Strong Answer Covers - A goal tied to Meta's focus on connection, considering both sides of the interaction: the reminded friend and the birthday person - A north-star metric that captures meaningful, two-way birthday interactions rather than raw notification clicks - Supporting metrics along the journey from reminder delivered to wish sent to reply or continued conversation - Guardrails for notification fatigue, privacy and sensitive cases such as friends who have died or people the user has distanced from - A way to measure the reminder's incremental effect, such as a holdout group ### Follow-up Questions - After a redesign, more wishes are sent but fewer birthday people reply. Is that a success? - How would you tell whether reminders create new interactions or only shift wishes people would have sent anyway? - How should the metrics treat users with thousands of friends who receive several birthday reminders every day?