Nonequivalent Control Group Before-After Design

Non-equivalent control group before-after design is a quasi-experimental research methodology in which two different groups (experimental and control) are used to evaluate the effects of an intervention. The control group is not randomly assigned and the groups differ, hence the term "non-equivalent." This design is utilized when it is not possible to use randomization to assign group members, making it a suitable choice if the researcher has strong expectations about the outcome of the intervention. In this design, the same group is assessed before and after the intervention has taken place. The data collected from the control group allows the researcher to compare outcomes between the groups and make inferences about the impact of the intervention. The strength of this study design is that the researcher can control for pre-existing differences between the two groups. This prevents the outcomes from becoming confounded by such differences.