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.
