ASEBA Research

Using the CBCL to Evaluate the Clinical Significance of Interventions

An article by Philip Kendall and colleagues of Temple University (Kendall, Marrs-Garcia, Nath, & Sheldrick, 1999) provides an excellent demonstration of using the CBCL to evaluate the clinical significance of a therapeutic intervention. In this article, Kendall describes a five-step procedure for combining traditional statistical tests with clinical equivalency tests to determine if a therapy program produces clinically meaningful as well as statistically significant treatment effects. In both the traditional and clinical equivalency tests, the treated group is compared with a normative group, rather than with an untreated control group. Using data from a study by Barrett, Dadds, & Rapee (1996), Kendall shows how the CBCL can be utilized for this type of analysis. In the study described, a group treated with cognitive behavioral therapy plus family management was evaluated with the CBCL 6 months post-treatment. Results indicated that (1) the treated group's mean CBCL Internalizing T score was not significantly different from the mean of the normative sample, and (2) the treated group's Internalizing score was significantly lower than the normal range upper bound of 60 (+1 SD). Kendall indicates that the advantage of using outcome measures such as the CBCL for this kind of analysis is that the published normative data based on large epidemiological samples provide “reliable estimates of general-population parameters.”

Reference: Kendall, P.C., Marrs-Garcia, A., Nath, S.R., & Sheldrick, R.C. (1999). Normative comparisons for the evaluation of clinical significance. Journal of Consulting & Clinical Psychology, 67, 285-299.