Which term is described as a randomized experiment or quasi-experimental designs used when experiments aren't possible?

• A. Natural Experiment
• B. Empirical Research
• C. Internal Validity
• D. Gold Standard

Answer: (D)

When you can’t run a true randomized trial, researchers turn to designs that imitate random assignment using natural variations in exposure. A natural experiment takes advantage of a real-world event or policy change that assigns treatment and control groups in a way that, in practice, resembles random distribution. This approach is a form of quasi-experimental design aimed at isolating causal effects despite the absence of deliberate randomization. It lets you compare outcomes across groups that are similar in many respects, attributing differences to the exposure rather than to other factors.

In contrast, the gold standard term refers to randomized trials where assignment is controlled by researchers, which isn’t feasible in some settings. Empirical research is a broad umbrella for data-driven study and doesn’t specify the design type, and internal validity is about how well a study supports causal conclusions, not a distinct design itself.