What is a cohort study?

A cohort study follows a group of people that were born at a similar date or period of time – be it a day, month, year or decade, for instance. It follows these people throughout their lives, and collects information from them at particular ages. By following the same people over time, these studies are able to tell us how and why people change as they get older. Next Steps is a cohort study following people born between 1 September 1989 and 31 August 1990.