An Introduction . . .
Since the mid-1960's, the number of therapy models has grown from 60 to more than 250.  At the same time, virtually all of the research data finds that the various treatment approaches achieve roughly equivalent results.  This is true of both the biological and well as the much bally-hoed cognitive and cognitive behavioral revolutions.  When all is said and done, virtually all of the data find that the various approaches work about equally well.  As leading outcome researcher Michael J. Lambert, Ph.D. summarizes, "Research carried out with the intent of contrast two or more bona fide treatments shows surprisingly small differences between the outcomes for patients who undergo a treatment that is fully intended to be therapeutic" (p. 158, 1994).

Such evidence makes clear that the differences between the various models–much promoted by the developers and marketers of the different approaches–can not account for the effectiveness of treatment.   Rather, the mountain of evidence for equivalent outcomes makes it clear that the similarities rather than differences between models account for the effectiveness of psychotherapy.  The question, of course, is what similarities approaches share that account for success?

The Facts...
Research points to the existence of four factors common to all forms of therapy despite theoretical orientation (dynamic, cognitive, etc.), mode (individual, group, couples, family, etc.), dosage (frequency and number of sessions), or specialty (problem type, professional discipline, etc.).  Research found the one factor dominates the lion's share of change, extratherapeutic or client factors, accounting for 87% of change. The remaining 13% of change can be attributed to therapeutic effects, wherein the other three common factors are found. In order of their relative contribution to change, these elements include: (1) Alliance Factors [8% or 60% of therapeutic effects]; (2) Allegiance Factors  [4% or 30% of therapeutic effects]; and (3) model or technique  [1% or 8% of therapeutic effects].  For more info/references: The Great Psychotherapy Debate [LEA, 2001].

Research on the four common factors makes clear that various therapeutic techniques (e.g., confrontation, the "miracle question," EMDR) are better viewed as different means of empowering one or more of the factors responsible for treatment outcome rather than unique to a specific treatment model.  A therapists allegiance to a specific model of therapy is four times more important than the model being employed! Incidentally, this meta-view of therapy models also happens to fit the way experienced clinicians actually practice. Surveys conducted over the last several decades have consistently found, for example, that clinicians tend to identify less with any one approach the longer they have been in the field.  Rather, experienced therapists tend to pick and choose from a variety of approaches in an effort to tailor treatment to the makeup and characteristics of the individual client.

Of course, the challenge to practicing clinicians–owing to the many choices available–is which technique(s) or approach(s) to adopt when working with a particular client?  In this regard, research conducted by Duncan, Hubble, & Miller (see Psychotherapy With Impossible Cases [Norton, 1977]; Changing the Rules [Guilford Press, 1992]) as well as others (for a thorough review see Chapter 14, The Heart & Soul of Change [APA, 1999]) shows that the client view of the presenting complaint, potential solutions, and ideas about the change process form a theory of change that can be used as the basis for determining, which approach, by whom, would be the most effective for this person, with that specific problem, under this particular set of circumstances. This same research shows that the probability for success is greater when the treatment offered fits with or is complementary to the client's theory.

So, what do these empirical facts mean in terms of day-to-day clinical practice? Click here to find out!