According to the University of New Mexico, a causal study examines a cause and effect between variables. Causality shows a directional relationship between an independent variable, or interaction between independent variables, and a dependent variable. Researchers often employ observational or experimental methods to derive causality.
A causal study must meet certain criteria. According to the University of Southern California’s Library Guide, a causal study contains “empirical association,” “appropriate time order” and “nonspuriousness.” Researchers must use empirical research methods to gather data, such as through observation and experimentation. Researchers must expose the independent variable before the dependent variable in order to show direction between the variables. The last component is for the researchers to insure that extraneous variables do not affect the dependent variable; this calls for the use of controls within the study. Causal studies must show a correlation between the variables; however, a correlation is not sufficient to show causation. These other steps are necessary to show causality within the study.
Other tools help researchers create a causal study. Random assignment and controls increase internal validity, which is the confidence that a causal study does not have contamination from extraneous variables. Causal studies conclude a directional relationship, but they do not verify the relationship undoubtedly.