BEHAVlOX T ~ Y 25, 147-158, 1994 Assessing the Clinical Significance of Outcome in Agoraphobia Research: A Comparison of Two Approaches EDWIN DE BEtnts University of Amsterdam R~CHARD VAN DYCK ANTON J. L. M. VAN BALKOM Free University, Amsterdam ALFRED LANOE P E T E R KOI~LE University of Amsterdam We evaluated two methods for characterizing clinically significant change in agora- phobia treatment research: The method proposed by Jacobson and colleagues (1991) and an alternative method, in which the endstate functioning of patients 0ow, medium, or high) was assessed by several criteria relevant for panic disorder with agoraphobia. Whenever possible, statistically determined cutoffpoints were appfied on these criteria. Comparison of the outcome revealed considerable consonance between both methods, although the Jacobson approach was somewhat more lenient in considering patients recovered. The reliable change index, an additional criterion proposed by Jacobson et al. in order to assess whether patients had experienced true change as a result of treatment, had little informational value: All patients who met the criterion of clini- cally meaningful change had reliably changed as well. Moreover, the reliable change index did not discriminate between patients with medium and low clinical endstatus. Evaluation of treatments for agoraphobia usually involves a comparison of the outcome of various treatments under controlled conditions. When a The authors thank Brigit van Widenfeit for her detailed editorial comments. We also thank the anonymous reviewers for their helpful comments on an earlier draft of this manuscript. Cor- respondence concerning this article should be sent to Edwin de Benrs, Ph.D., Department of Clinical Psychology, University of Amsterdam, Roetersstraat 15, 1018 WB Amsterdam, The Netherlands. 147 0005-7894/94/0147-015851.00/0 Copyright 1994 by Association for Advancement of Behavior Therapy All rights of reproduction in any form reserved.