In evaluations of the effects of healthcare interventions, a study in which people are identified according to current risk status or exposure, and followed forwards through time to observe outcome. Prospective studies ask how a suspected risk or protection factor (e.g., a specific nutritional behaviour) affects a specific pathogenesis. They first recruit appropriate participants, and then look how the exposures influence disease risk in these people over the following months or years. 

Prospective studies are considered to generate more accurate results of stronger evidence than retrospective studies.