Research on psychotherapy efficacy and effectiveness: Between scylla and charybdis?

Clinical researchers have recently begun to explore differences between psy chotherapy outcome studies that focus on efficacy and those that focus on e ffectiveness. The authors provide concise descriptions of these research mo dels, followed by more extended consideration of the most important concept ual and empirical distinctions between the two. Research on the efficacy/ef fectiveness distinction is then put into context: The common treatment vari ables that also influence treatment outcomes are reviewed. Fifty years of r esearch on psychotherapy outcomes are next considered; contemporary researc h on the efficacy and effectiveness research models is emphasized. A descri ption and evaluation of current efforts to heighten the value of technique- focused research to clinicians follow. The authors conclude by anticipating some promising future directions in this research domain.