Identify the correct statements.

Both panel study and cohort study are types of longitudinal research, tracking subjects across repeated points in time.

A panel study follows the same individuals over successive waves, which is inherently longitudinal, not cross-sectional.

A cohort study follows a group sharing a common characteristic over time, again ruling out a cross-sectional label.

Statements three and four wrongly file these designs under cross-sectional research, making combinations that use them fail.

Cross-sectional research collects data at a single point across many cases instead.

A cohort shares an event such as birth year, while a panel is a fixed sample re-surveyed over time.