Using clinical significance in psychotherapy outcome research: the need for a common procedure and validity data.

It is recommended that an estimate of clinical significance be included in all psychotherapy outcome studies and that this estimate be based on the work of Jacobson and Truax (1991). The concept of clinical significance is defined and put in the context of broadly accepted statistical methods along with its advantages and a rationale for using the Jacobson methods. One implication of this recommendation is that the use of the term will have a standard meaning. Examples of loss of meaning are provided and suggest that conclusions about best practices will be affected unless such a voluntary step is taken. Some problems with the concept of clinical significance are noted and a call for validity studies is made.