Cohort vs Experimental: A cohort study is best described as?

• A. Observational; The researcher cannot allocate exposure
• B. Experimental, with random allocation of exposure
• C. Cross-sectional survey
• D. Qualitative study

Answer: (A)

Cohort studies are observational investigations where the exposure is not allocated by the researcher; instead, people are grouped based on whether they were exposed and then followed over time to see who develops the outcome. This prospective or retrospective follow-up allows researchers to observe incidence and compare risk between exposed and unexposed groups without intervening.

This design is distinct from experimental studies, where the investigator assigns exposure and often randomizes participants to groups. It also differs from a cross-sectional survey, which provides a snapshot at one point in time, and from qualitative research, which focuses on non-numeric data and meanings rather than numerical incidence or risk estimates.

So, the description that best fits a cohort study is that it is observational and the researcher cannot or does not allocate exposure.