The What Works Clearinghouse (WWC) Standards Briefs explain the rules the WWC uses to evaluate the quality of studies for practitioners, researchers, and policymakers. This brief explains what baseline equivalence is and why it matters. As part of the WWC review process for certain types of studies, reviewers assess whether the intervention group…

The Hawthorne and placebo effects in educational experiments were examined over a 20-year period, as reported in the ERIC, Dissertation Abstracts International, and Psych Info data bases. The literature searches identified 325 studies in education employing the relevant control procedures, and each study was coded for the type of placebo…

Although informal assessments of caregiver training and support groups have been positive, empirical evidence of their beneficial impact is needed. To evaluate a group program for families of elderly parents, a pre/postmeasure, experimental/control group design was implemented. Adults participating in two workshops on "Your Aging…