Cohort Study

A 'cohort' is a group of people clearly identified: a cohort study follows that group over time, and reports on what happens to them. A cohort study is an observational study, and it can be prospective (following people forward over time) or retrospective (looking at what happened in the past). For example, a cohort study of 4th graders could follow them forward as they age, or look back at their previous health and school histories.