Ex post facto design nature – UGC NET Question

Ex post facto research, also called causal-comparative research, looks for possible cause–effect relationships by studying groups that differ on some outcome that has already occurred. The researcher does not manipulate the independent variable but observes existing differences and attempts to infer causes. This design is useful when experimental manipulation is unethical or impractical. Therefore, investigating causes after the effect has occurred is characteristic of ex post facto research.

Option A:
Option A correctly names ex post facto research, where “after the fact” indicates that the outcome is already present. Groups are compared on presumed causal factors that have not been controlled by the researcher. Because there is no manipulation and the effect comes first, this option fits the stem and is correct.

Option B:
Experimental research actively manipulates one or more independent variables and controls extraneous factors to test causal hypotheses. It does not wait for effects to occur naturally and then look backward. Thus, experimental research does not match the design described.

Option C:
Correlational research examines statistical relationships between variables without attempting to infer causality in a strong sense. It may be cross-sectional and does not necessarily start from an existing group difference on an outcome. So it is not the best label here.

Option D:
Longitudinal research follows the same participants over time to study change; it may be experimental or non-experimental. It is defined by the time dimension rather than by investigating causes after effects, so it is not the correct answer.