In this type of research, the independent variable is not within the control of the researcher.

• A. Ex Post Facto
• B. Experimental
• C. Quasi-Experimental
• D. Correlational

Answer: (A)

Ex post facto research relies on events or conditions that have already occurred before the study begins. The independent variable is not within the researcher’s control because it is pre-existing and cannot be manipulated or assigned by the investigator. Instead, participants are grouped according to these prior conditions (for example, exposure that happened in the past) and outcomes are compared. Because there is no random assignment or active manipulation, causal conclusions are harder to draw and the focus is on associations between pre-existing factors and outcomes. This differs from experimental designs, where the independent variable is actively manipulated and participants are randomly assigned to conditions; quasi-experimental designs involve some manipulation but lack full randomization; and correlational studies observe relationships without manipulation at all. The key feature here is that the independent variable cannot be controlled by the researcher, which makes ex post facto the best fit.