What describes a longitudinal study in relation to its duration?

A longitudinal study is characterized by its extended duration, as it involves observing the same subjects over a significant period of time. This design allows researchers to track changes and developments in participants' behavior, traits, or conditions across various points in time. By focusing on the same individuals, longitudinal studies can provide insights into trends, causality, and long-term outcomes that shorter studies may not capture.

The length of a longitudinal study is critical because it gives researchers the opportunity to gather data that reflects changes that may occur due to age, experience, or other life events. This approach is particularly beneficial in fields like developmental psychology, where understanding how individuals change throughout their lives is fundamental.