Campbell and Stanley (1963) point out that although the two-group pretest-posttest design ensures a degree of internal validity, _____.
A) identifying causal relationships is difficult
B) establishing the statistical significance of your results is difficult
C) it does not preclude problems with external validity
D) None of the answers is correct.

Question

Quizplus · Accepted Answer

The two-group pretest-posttest design can control for internal validity threats but does not address external validity issues, which concern the generalizability of the findings to other settings, populations, or times.

Campbell and Stanley (1963) Point Out That Although the Two-Group