What is defined as a research design that follows the same subjects over a prolonged period?

A research design that follows the same subjects over a prolonged period is identified as a longitudinal study. This approach involves repeated observations or measurements of the same variables over time, which allows researchers to detect changes and developments within the same subjects. By doing so, longitudinal studies can provide insights into trends, causal relationships, and the dynamics of change, making them particularly valuable in fields like healthcare and social sciences.

In contrast to cross-sectional studies, which capture a snapshot of a population at a single point in time, longitudinal studies emphasize the temporal aspect of data collection. Case studies focus on a deep exploration of a specific instance or subject but do not necessarily track these subjects over a long duration. Experimental studies involve the manipulation of variables to establish cause-and-effect relationships but do not inherently follow subjects over time. The unique characteristic of observing the same subjects repeatedly is what distinctly defines longitudinal studies as a powerful research design.