How is a longitudinal study defined?

A longitudinal study is defined by its design, which involves repeated observations of the same variables over an extended period. This methodology allows researchers to track changes and developments in the subject matter over time, making it particularly useful for understanding trends, patterns, and the long-term effects of various factors.

In contrast to cross-sectional studies, which collect data at a single point in time and provide a snapshot view, longitudinal studies provide dynamic insights by examining how variables may evolve or interact over time. This can help in establishing causal relationships and understanding the development of phenomena, whether that involves tracking a cohort's health, academic progress, or behavioral changes.

The focus of a longitudinal study is not confined to whether the data is qualitative or quantitative, and thus it does not solely rely on qualitative data; instead, it can encompass a broad range of data types collected repetitively. By capturing data over different time points, researchers are better equipped to analyze trends and make informed conclusions about the subjects being studied.