Ranking a Friend's Fundraiser Against Their Event in Facebook Notifications

You are the product manager for Facebook notifications. Suppose a user's friend has a fundraiser running and is also hosting, or planning to attend, an event. How would you work out the trade-offs between notifying the user about the friend's fundraiser and notifying them about the friend's event, and how would you decide which one to show? ```hint Compare value and cost for this person A notification is worth something different to the recipient, to the friend and to the platform, and it also has a cost when it feels like spam or pressure. Ask how those values shift with who the recipient is, how close they are to the friend and how time-sensitive each item is. ``` ### Clarifying Questions - Which surfaces are in scope: push notifications, the in-app notification list, or both? Push slots are much scarcer than positions in the list. - Is this a strict choice of one, or could both be sent, one delayed, or the two combined into a single notification? - Should an event the friend created count for more than one they only plan to attend? - What outcome is the notifications team judged on: actions taken on notifications, long-term engagement and retention, or the success of the fundraisers and events themselves? ### What a Strong Answer Covers - The goals of notifications overall and of fundraisers and events, and where those goals conflict - How to value one notification: the benefit to the recipient and the friend against costs such as fatigue, guilt over a request for money and users turning notifications off - Signals that predict whether this recipient will act on each item, such as closeness to the friend, distance to the event, timing and past giving or attending - A decision rule or ranking approach, including the option of sending neither, validated by an experiment with primary metrics and guardrails - Edge cases: sensitive fundraisers, events about to start, private events and recipients who already acted ### Follow-up Questions - In a test, fundraiser notifications raise more money but also increase the rate at which people turn notifications off. How do you decide? - A donation and an RSVP are measured in different units. How would you compare them in a single ranking? - How would you design the experiment when changing what recipients see also changes how much money and attendance the friends' fundraisers and events receive?