====== Longitudinal observational cohort study ======

A longitudinal [[study]] (or longitudinal survey, or panel study) is a research design that involves repeated [[observation]]s of the same variables (e.g., people) over long periods of time, often many decades (i.e., uses longitudinal data). It is often a type of [[observational study]], although they can also be structured as longitudinal [[randomized]] experiments.

[[Retrospective]] case control

[[Prospective cohort study]].