What does the term "longitudinal study" refer to?

The term "longitudinal study" refers to a research design that involves repeated observations of the same variables over an extended period. This approach allows researchers to track changes and developments in the subjects being studied, providing valuable insights into patterns over time. Longitudinal studies are particularly useful for examining trends, causality, and the dynamics of change in social, psychological, health-related, or behavioral factors.

By collecting data at multiple time points, researchers can identify how variables are related across time, making it easier to observe the effects of time on various aspects of the subjects studied. This method contrasts with cross-sectional studies, which examine a snapshot of data at a single point in time, and it provides a richer context for understanding the continuity and changes in the studied phenomena.