When participants in one treatment condition have characteristics that are different from the characteristics of participants in another treatment condition, then ____ may be threatened.
A) internal validity
B) external validity
C) reliability
D) accuracy

Question

Quizplus · Accepted Answer

Internal validity is the extent to which a study accurately shows cause-and-effect relationships. When participants in one treatment condition have different characteristics than those in another treatment condition, it becomes difficult to attribute any observed differences between the two groups to the treatment itself rather than to the pre-existing differences in participant characteristics. Therefore, the internal validity of the study may be threatened.

When Participants in One Treatment Condition Have Characteristics That Are