+An **observational study** carefully examines subjects or phenomena without researcher intervention, capturing events as they naturally unfold. Researchers observe participants and measure outcomes, often exploring relationships without assigning interventions or using a strict [Control Group](/wiki/control_group), making it challenging to infer [Causation](/wiki/causation).
+## See also
+- [Experiment](/wiki/experiment)
+- [Correlation](/wiki/correlation)
+- [Bias](/wiki/bias)