The dodo-bird has been extinct for almost three centuries, thanks to the Dutch east Indian shipping company which made Mauritius a stopping point on their sea travels and altered the living conditions on the island in such a way that the dodo died. In the caring sector, the dodo-bird is however alive and kicking thanks to a short article of Saul Rosenzweig (1907-2004) from 1936. This psychologist researched the different effects of specific forms of psychotherapy and wondered whether method A was in any way better than method B or C. Soon enough, he found that the effectiveness of each method was very much comparable and it made little difference which was used. For that reason, Rosenzweig opened his article with a quote from Alice in Wonderland citing the dodo-bird who organised a running competition in reply to the question who had won the race: “Everybody has won, and all must have prizes”.

If the effects of all psychotherapy is very comparable, regardless of the specific interventions used, the theoretical underpinning of method A, B or C becomes questionable. The theories in use can explain why a specific method works, but not why all have similar effects despite different interventions and approaches being used. That calls for a different explanation. Saul Rozenzweig introduced the hypothesis that the effect of therapy should not be attributed to the specifics of a certain method, but to what all had in common, the so-called ‘common factors’.
The debate on what makes therapy work is thus refocused on those elements that all interventions share, such as the therapeutic relationship, showing respect for the client(s), and giving hope. If such common factors are quintessential to effects, it is critical to focus quality systems on them, as well as the training and selection of therapeutic professionals.

Although Saul Rosenzweig`s article is almost 80 years old, the discussion on what makes therapies work is still going strong. It has also been expanded and currently not only covers psychotherapy, but social work as well. Several authors follow the path taken by Rosenzweig and attribute the effect of therapies to several common factors. They refer to Michael Lambert or Bruce Wampold to state that 40% of the therapeutic effect can be attributed to factors outside the scope of the therapy, 30% to general working factors, 15% is a placebo effect and 15% the contribution of the specific method. Others refer to Kieran McKeown and attribute 40% of the effect of therapy to client characteristics and social support, 30% to the therapist-client relationship, 15% to client hopefulness and 15% to the therapeutic technique. The proportions are the same but with slightly different categories. The key message is however the same: the choice of a specific intervention is much less important for success than other factors. A recent study on the effects of psychotherapy for depression came to the same conclusion: different psychotherapeutic interventions have comparable benefits.
The recent contributions to social work literature focusing on relationship based social work (e.g. by Gillian Ruch and her colleagues) match this thinking as they zoom in on one of the common factors rather than specific interventions.

This text was written by Jan Steyaert
Date of first publication: 12-2011
Date of latest revision: 06-2019