Understanding processes of change: how some patients reveal more than others-and some groups of therapists less-about what matters in psychotherapy.
OBJECTIVE
We identify difficulties researchers encounter in psychotherapy process-outcome investigations, and we describe several limitations of the popular "variance accounted for" approach to understanding the effects of psychotherapy.


RESULTS
Using data simulations, we show how the expected correlation between an excellent measure of therapy quality and outcome would be surprisingly small (approximately .25) under conditions likely to be common in psychotherapy research. Even when we modeled conditions designed to increase the likelihood that strong process-outcome relationships would be observed, we found that the expected correlations were still only in the modest range (.38-.51).


CONCLUSIONS
We discuss the implications of our analysis for the interpretation of process-outcome findings as well as for design considerations in future investigations.
a Department of Psychology , University of Pennsylvania , Philadelphia , PA , USA.
Robert J
RJ
Derubeis
Lois A
LA
Gelfand
Ramaris E
RE
German
Jay C
JC
Fournier
Nicholas R
NR
Forand
D006801:Humans; D011369:Professional-Patient Relations; D013811:Psychotherapeutic Processes; D011613:Psychotherapy; D012650:Self Disclosure; D016896:Treatment Outcome