A cohort is defined as a group of people sharing a common temporal demographic experience who are observed through time. In addition to being restricted to a common temporal demographic experience, cohorts may also be restricted based on the other geographic or demographic filters used for the population -- the key point is that the only additional restriction placed on the cohort, relative to the whole population, is based on the temporal experience.
Common types of cohorts
|Cohort type||Event that has to occur within a specified time period|
|School class cohort||Enrollment in or graduation from a particular school|