====== Observational study ======

Of, relating to, or founded on observation, especially founded on observation rather than experiment.
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:
   - The researcher observes and collects data without intervening or altering the conditions.
   - Participants or subjects are studied in their natural settings, and no experimental manipulation is applied.
   - Common observational methods include cohort studies, case-control studies, and cross-sectional studies.

see [[Observational study]].