North-Star and Guardrail Metrics for Launching Facebook Events in 2011

It is 2011 and you are the product manager planning the launch of Events on Facebook, a feature that lets someone set up a gathering with a time and place, invite friends, and see who plans to come. Before launch, decide which metrics the team should adopt as its goals. Say which metric you would make the primary goal, which supporting metrics you would track alongside it, and why you chose them over the alternatives. ```hint Follow both sides of an event Every event has a host and a set of guests. A goal that rewards only one side can look healthy while the other side quietly loses interest, so ask what a good outcome looks like for both. ``` ### Clarifying Questions - Which surfaces are in scope at launch: only the desktop site, or the mobile apps as well, given how quickly mobile use was growing at the time? - Does Events cover only gatherings among friends, such as parties and birthdays, or also public events hosted by Pages for venues, bands and organizations? - What should Events do for Facebook as a whole: deepen engagement among existing users, attract new users through invitations, or give Pages a reason to build audiences? - Can the team observe anything about real attendance, or only what guests say in their responses? ### What a Strong Answer Covers - The purpose of Events for hosts, guests and Facebook, and a primary goal that follows from that purpose. - A precisely defined primary metric (unit, threshold and time window) and why it beats obvious candidates such as events created or invitations sent. - Supporting metrics for each stage of an event's life: creation, invitation, response, the event itself and what happens afterwards. - Guardrails against invitation spam, notification fatigue, privacy mistakes and harm to the rest of Facebook. - How the team would use the metrics at launch: baselines, segments and experiments. ### Follow-up Questions - After launch, the number of events created climbs quickly, but the share of invitations that get any response keeps falling. How do you read that, and what do you do? - How would you show that Events adds engagement to Facebook rather than moving activity away from messages, wall posts or Groups? - Pages want to promote large concerts and ticketed shows through Events. How would your goals change to support them without crowding out small gatherings among friends?