Noun Phrase
/lɒŋ.ɡɪ.tjuː.dɪ.nəl ˈstʌ.di/

Longitudinal Study

Studies that follow the same group of people over a long period to observe how specific factors affect outcomes over time.

Purpose: To identify trends and potential causation by examining how variables change.Example: Tracking dietary habits and heart disease risk in the same group for 20 years.