What is the primary focus of a longitudinal design in research?

In research, a longitudinal design is specifically focused on studying a single group of participants over an extended period of time. This approach allows researchers to observe changes and developments in the same individuals, making it particularly useful for examining how variables evolve and influence behavior or outcomes over time.

The emphasis on a single group enables researchers to collect data at multiple points, which can highlight trends and patterns that occur as participants age or as circumstances change. This method contrasts with cross-sectional designs, where multiple groups are assessed simultaneously and comparisons are made at one specific point in time. By using a longitudinal design, researchers gain deeper insights into the dynamics of development, behavior, and other psychological phenomena, providing a clearer picture of long-term effects and trends.