In the observation-treatment-observation situation,a typical threat to validity is the fact that:
A) natural treatments are likely to produce long-term carry-over effects
B) changes in the subjects' behavior result from experiences of the participants prior to the first observation period
C) a nonequivalent control group always results in selection bias
D) participants are randomly assigned to treatment and control conditions

Question

Quizplus · Accepted Answer

Natural treatments can lead to long-term carry-over effects, which can confound the results by affecting the post-treatment observations, thus threatening the validity of the study.

In the Observation-Treatment-Observation Situation,a Typical Threat to Validity Is the Fact