While much attention has been paid to the effectiveness of various "brands" of therapy there is a growing understanding that therapeutic change occurs due to a number of nonspecific factors that are not exclusive to any one approach.
These factors have a much greater influence on outcome than the contribution made by approach-specific theory and technique; in Lambert's (1986) review of empirical studies, common therapeutic factors accounted for 30% of the therapeutic effect, technique 15%, expectancy (placebo-effect) 15% and spontaneous remission 40%.[1]