Longitudinal study

A longitudinal study follows subjects over a certain time period and collects data at specific intervals. Longitudinal studies are powerful study designs. They are particularly useful in medicine as they enable researchers to determine important associations and answer questions regarding prognosis. For example, “when is an athlete able to return to play after a forearm fracture?” is a question that can be answered with a longitudinal study. In this chapter, we will define the three main types of longitudinal studies, analyze examples of prominent longitudinal studies in the literature, and offer advice on the steps needed to perform a longitudinal study.