WWC review of this study

Masked Intervention Effects: Analytic Methods for Addressing Low Dosage of Intervention

Lochman, John E.; Boxmeyer, Caroline; Powell, Nicole; Roth, David L.; Windle, Michael (2006). New Directions for Evaluation, n110 p19-32. Retrieved from: https://eric.ed.gov/?id=EJ792293

  • Randomized Controlled Trial
    , grade

Reviewed: October 2011

No statistically significant positive
Meets WWC standards without reservations
External behavior outcomes—Indeterminate effect found for the domain
Comparison Period Sample Intervention
Significant? Improvement

Behavior Assessment System for Children (BASC) Externalizing Composite Teacher Rating Scale

Coping Power vs. business as usual


Grade 5;
224 students





Evidence Tier rating based solely on this study. This intervention may achieve a higher tier when combined with the full body of evidence.

Characteristics of study sample as reported by study author.

  • Female: 36%
    Male: 64%
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The study took place across seven elementary schools in Alabama. The student intervention was delivered by pairs of researchers through weekly small-group sessions in the school building. The parent component was delivered through sessions in the school building in the afternoons or evenings.

Study sample

The sample consisted of fifth-grade students who were in the top 30% of grade 4 students based on teacher ratings of aggressive behavior. A total of 240 aggressive boys (64%) and girls (36%) were randomized to receive the intervention (n = 120) or be in a comparison group (n = 120). Outcome data were available for 224 boys, with 112 students in each group. The gender and race/ethnicity distribution and family composition were similar across participants in the intervention and comparison conditions. Sixty-nine percent of the children self-identified as African American, 30% as Caucasian, and 1% as another race or ethnicity. Forty percent of the children lived with a single mother.

Intervention Group

This study used an abbreviated version of the Coping Power program. Students participated in 24 child group sessions led by pairs of researchers; each group included five to six students. Sessions focused on coping and problem-solving skills, as well as strategies for enhancing social relationships and resisting peer pressure. The children had an overall attendance rate of 93%. Parents of students in the intervention group were invited to take part in parent sessions held in the school two times each month. These groups focused on behavior management skills and improving family problem solving, communication, and cohesion. The groups included parents and primary caregivers of the target children. Thirty percent of parents did not attend any of the 10 sessions offered.

Comparison Group

The comparison group did not participate in Coping Power. Comparison children received services typically offered by their schools. The parents of these students did not participate in any parent sessions.

Outcome descriptions

This study used teacher ratings on the Behavior Assessment System for Children (BASC) external behavior scale, conducted before and after the intervention. For a more detailed description of these outcome measures, see Appendix B.

Support for implementation

Pairs of researchers implemented the intervention. No information is provided about training.


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