A Special Unit in a Child Welfare Agency Provides an Innovative

Multiple Choice

A special unit in a child welfare agency provides an innovative treatment to those cases with the worst assessment scores. To evaluate the unit's effectiveness, the degree of improvement among its clients in assessment scores is compared to the degree of improvement among cases in other units. The evaluation finds that the cases in the special unit had a significantly higher average degree of improvement than did the cases in the other units. From this information we can conclude that:

A) the special unit is effective.
B) the difference in outcome might be due to statistical regression to the mean.
C) the study had a high degree of internal validity.
D) Both a and c are correct.