Static Cohort
Intermediate PronunciationEN/ˈstætɪk ˈkoʊhɔːrt/
A static cohort is a group of users whose membership is decided once, at the moment the group is built, and never changes afterwards no matter what those users do later.
The membership condition runs once and the resulting list of identifiers is stored, after which every report runs against that closed list. Its main use is following exactly the same people over time, for instance everyone acquired in one campaign. It differs from a dynamic cohort, which re-evaluates its condition on every run and therefore changes size. A frequent misreading is treating a static cohort's declining activity as product-wide churn: the group decays by construction, because no new member can ever enter it.
FAQ
A static cohort stores the list of people, while a saved segment stores only the definition and recomputes membership on every run. That is why a static cohort keeps its size and a saved segment's size moves over time.