A cohort is a collection of individuals who are grouped together in a statistical analysis because they have at least one particular characteristic in common. For example, a cohort could be college graduates born in 1980. Often a cohort study tracks a cohort over extended periods of time.

Some teachers organize into cohorts, or groups of peers who do much or all of their academic work and practice teaching together (Mather & Hanley, 1999; Shapon-Shevin & Chandler-Olcott, 2001). They have justified the cohort models on three grounds. First, it is hoped that cohorts create mutual intellectual and academic stimulation, including the sharing and critiquing of ideas, materials, and other resources. Second, it is hoped that cohorts facilitate the forming of supportive social ties among students, and that the ties will become lasting professional contacts after graduation. Third, it is hoped that cohort programs will be easier to easier to organize and administer, since cohort students, by definition, take a single set of classes that occur at common times.