What type of study is considered a cohort study?

A cohort study is characterized as a longitudinal study that follows a group of individuals over time to observe how certain exposures affect outcomes, such as the development of diseases or health conditions. In this type of study, participants are selected based on their exposure status and are followed to measure how different factors influence their outcomes.

The longitudinal nature of cohort studies allows researchers to establish timelines for the effects of exposures and to determine incidence rates over time. This approach is particularly useful for examining the natural history of diseases and for identifying potential risk factors.

In contrast, cross-sectional studies assess data at a single point in time and do not track changes over time. Case-control studies, on the other hand, compare individuals with a specific outcome (cases) to those without it (controls) but do not follow participants over time in the same way. Experimental studies involve interventions and random assignments, which differ fundamentally from the observational design of cohort studies. Thus, identifying cohort studies as longitudinal is crucial for understanding their structure and purpose.