The pretest in a pretest-posttest control group design is both its main strength and weakness. The pretest allows for the measurement of change and comparison between groups, but it can also sensitize participants to the intervention, possibly affecting the outcomes (pretest reactivity). “While the pretest allows for baseline measurement, it may also influence participants’ responses on the posttest, posing a threat to internal validity.”
[Reference: Helwig, A. A. (2020). CPCE Study Guide and Review; Royse, D., Thyer, B. A., & Padgett, D. K. (2016). Program Evaluation: An Introduction., ]
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