PSYCHOTHERAPY and counseling for individuals  and Couples – Corvallis OR

Seth Bernstein, Ph.D.


theory of


According to Scott D. Miller and Barry Duncan’s web site,, four weighed factors account for change in psychotherapy: extra therapeutic factors – 40 per cent; collaborative relationship – 30 per cent; placebo, hope, expectancy – 15 per cent; and structure, model, technique – 15 per cent. Yet most psychotherapists focus on refining skills in their favourite therapeutic model of practice. 

Miller and Duncan report that since the mid-1960s, the number of therapy models has grown from 60 to more than 250. I have studied many of these models and teach a few.Miller and Duncan are not trying to say that psychotherapy does not work – they can cite many studies saying that it does – but they do think we focus too much on particular differences among therapies.
They suggest that various approaches work about equally well, and that it is the similarities, rather than the differences, that make therapy effective. Which takes us back to the four factors.Miller and Duncan are also not saying that we should ignore models and techniques. But they do suggest that in discussion about what works in therapy, too much attention is paid to the elements that interest therapists, like models and techniques, and not enough to the other partner in the therapeutic process – the client.

By focusing on what Miller and Duncan call the “client’s theory of change,” therapists can tap into those extra therapeutic factors that make up 40 per cent of change in therapy. In a section on client competence in their 2000 book The Heroic Client, Miller and Duncan encourage therapists to cast the client in the role of “primary agent of change." They suggest that therapy is most successful when clinicians pay more attention to the client’s ideas about what works best for them and then follow the client’s lead in, letting the choice of techniques be guided by the client’s wisdom.


The excerpts above are taken from an article written by Kate Kitchen titled, "Do Therapists Know What Clients Really Want." It describes the work of Scott Miller and Barry Duncan related to their "theory of change" model of therapeutic effectiveness. This model is described in many articles they have co-authored, but most extensively in their book, The Heroic Client.