How can we compare different psychotherapies? Why are they all effective?

The relationship between different schools of psychotherapy can be defined by locating them in terms of a more general, cognitive, theory. They differ in respect (a) of the level in the patient's hierarchy of schemata that is considered and addressed, (b) of the stages in the procedural sequence organizing aim-directed action at which treatment is aimed, (c) as to whether or not attention is paid to structural and defensive aspects of cognitive organization, and (d) according to where intervention is aimed in terms of the cycle of cognitive reorganization. The equivalent effectiveness of different methods is explained as being the result of the patient's capacity to integrate differently located treatment-induced changes into similar revisions of his system. Some implications of this view are indicated.