The Longitudinal Design

In a longitudinal design, participants are studied repeatedly, and changes are noted as they get older. The time spanned may be relatively short (a few months to several years) or very long (a decade or even a lifetime).

 

The longitudinal approach has two major strengths. First, because it tracks the performance of each person over time, researchers can identify common patterns as well as individual differences in development. Second, longitudinal studies permit investigators to examine relationships between early and later events and behaviors. Let’s illustrate these ideas.

Correlational

The investigator obtains information on participants without altering their experiences.

Permits study of relationships between variables.

Does not permit inferences about cause-and-effect relationships.