Longitudinal studies are research methods that involve repeated observations of the same subjects over a period of time. This approach allows researchers to track changes and developments in various aspects, such as behavior, health, or social conditions. By collecting data at multiple points, longitudinal studies can provide insights into trends and causal relationships. These studies are often used in fields like psychology, sociology, and medicine. For example, a longitudinal study might follow a group of children from birth to adulthood to examine how early experiences influence later outcomes. This method is valuable for understanding long-term effects and patterns.