Prospective studies are research studies that follow a group of individuals over a period of time to observe and analyze trends, changes, or outcomes. These studies typically involve collecting data from participants at multiple points in time and are often used to investigate the causes and effects of certain conditions or behaviors. Prospective studies are valuable for identifying risk factors for diseases, tracking the progression of conditions over time, and evaluating the effectiveness of interventions. They are often used in the fields of public health, epidemiology, and clinical research.