Group Level Clinical Significance: An Analysis of Current Practice

Measures of clinical significance offer important information about psychological interventions that cannot be garnered from tests of the statistical significance of the change from pretest to posttest. For example, post-intervention comparisons to a nonclinical group often offer valuable information about the practical value of the change that occurred. This study explored the manner in which researchers conduct clinical significance analyses in an effort to summarize the effectiveness of an intervention at the group level. The focus was on the use of the original Jacobson and Truax ( Journal of Consulting and Clinical Psychology, 59 , 12–19, 1991 ) method and the normative comparisons method due to Kendall et al. ( Journal of Consulting and Clinical Psychology, 67 , 285–299, 1999 ). The results highlight that although the Jacobson and Truax method is routinely adopted for summarizing group-level clinical significance, advanced strategies for summarizing the results are very infrequently applied. Further, the Kendall et al. method, which provides valuable and distinct information regarding how the treated group is performing relative to a normal comparison group, is rarely adopted and even when it is it is often not conducted appropriately. Recommendations are provided for conducting group-level clinical significance analyses.