Longitudinal research is a study method that involves observing the same subjects over an extended period. This approach allows researchers to track changes and developments in individuals or groups, providing valuable insights into trends and patterns. It is commonly used in fields like psychology, sociology, and healthcare to understand how certain factors influence outcomes over time. One key advantage of longitudinal research is its ability to establish cause-and-effect relationships. By collecting data at multiple points, researchers can see how variables interact and evolve. This method contrasts with cross-sectional studies, which only capture a snapshot of data at one moment in time.