**Cohort**is generally defined as a group of people within a population who are assumed to have identical exposures during a specified exposure period. The use of

**Cohort**s is a necessary simplifying assumption for modeling exposures of a large population. For the exposure assessment, the population was divided into a set of

**Cohort**s such that

1) each person is assigned to one and only one

**Cohort**, and

2) all the

**Cohort**s combined encompass the entire population.

**List of books: Cohort**