User Profile

A user profile is the set of durable attributes attached to one user, such as city, plan and first-seen date, stored apart from events and usually holding only the latest value.

A profile is in practice one row per user holding that user's properties, updated by an identify call or derived from the events themselves. The key difference from an event property is timing: an event property is frozen at the moment the event is recorded, while a profile property is overwritten in place. That produces a common analysis error: segmenting a three-month report by plan places a user who upgraded yesterday under the new plan for all three months. Questions that depend on the user's state at the time need the attribute recorded on the event itself, or a stored history of profile changes.