Of the following, which is the greatest threat to the internal validity of even a well-designed nonequivalent control pretest-posttest group design?
A) a history confound
B) statistical regression
C) a selection confound
D) maturation

Question

Quizplus · Accepted Answer

A selection confound is the greatest threat to internal validity in a nonequivalent control pretest-posttest group design. This is because the control group and experimental group were not created through random assignment, leaving the possibility that there are systematic differences between the two groups that could affect the outcome of the study. A history confound refers to specific events occurring during the study that could affect the outcome. Statistical regression refers to the tendency of extreme scores on the pretest to become less extreme on the posttest, which can affect the interpretation of the results. Maturation refers to natural changes that occur over time in the participants, which can also affect the outcome of the study, but it is not as great of a threat as a selection confound.

Of the Following, Which Is the Greatest Threat to the Internal