For other meanings see cohort

In statistics and demography, a cohort is a group of subjects — most often humans from a given population — defined by a condition on their date of birth. For example, Canadian women born in the year 1950 would form a cohort, when studied from a point of view such as their health or mortality, or education, or marriages. Studies of cohorts often track them over extended periods of time, and return to the same sample groups decades later.