Which of the following best defines a longitudinal study?

A longitudinal study is defined as a research method that collects data from the same subjects over an extended period. This approach allows researchers to observe changes and developments in the participants over time, such as how behaviors, attitudes, or conditions evolve. By repeatedly measuring the same subjects, researchers can establish patterns, identify trends, and infer causal relationships that might not be visible in cross-sectional studies, where data is collected at a single point in time.

The focus on repeated observations can lead to deeper insights into the temporal dynamics of the phenomena being studied, enabling the study of developmental changes, long-term effects, and the progression of conditions across different life stages or circumstances. This time dimension is what distinguishes longitudinal studies from other research designs.