Establishing clinically significant change: increment of precision and thedistinction between individual and group level of analysis

Some essential adaptations to the method for determining clinically signifi cant change originally introduced by Jacobson, Follette and Revenstorf [Jac obson, N. S., Follette, W. C. & Revenstorf, D. (1984a). Psychotherapy outco me research: methods for reporting variability and evaluating clinical sign ificance. Behavior Therapy, 15, 336-352.] are presented. One adaptation dea ls with the failure in the original method to distinguish between analysis at the individual versus analysis at the group level. A second adaptation e ntails the provision of a closer approximation of the underlying true score s. This refinement represents an enhancement in precision. Specific aspects of this refinement may be understood in terms of a correction for error-ba sed regression to the mean. Taking into account these adaptations, new proc edures are described for determining (clinically significant) change. Some guidelines for the publication of outcome findings are also presented. (C) 1999 Elsevier Science Ltd. All rights reserved.