The internal validity of the pre-post designs is threatened by
A)threats related to time.
B)threats related to differences between groups.
C)differential effects.
D)the other three choices are all threats to pre-post designs.

Question

Quizplus · Accepted Answer

Pre-post designs are vulnerable to threats related to time, which may include maturation, regression to the mean, and history effects, among others. These threats may impact the internal validity of the study by leading to erroneous conclusions about the effectiveness of the intervention. Therefore, researchers must be vigilant in addressing these threats when designing and interpreting pre-post studies. Option B refers to threats related to differences between groups, which are a concern in experimental designs, but not in pre-post designs. Option C refers to differential effects or interactions between variables, which are also a concern in experimental designs, but not in pre-post designs. Option D is incorrect because only option A accurately describes the unique threats to pre-post designs.

The Internal Validity of the Pre-Post Designs Is Threatened by