CRITICAL COMMENTS ON THE STATISTICAL-METH ODS IN GRAWE, DONATI AND BERNAUER - CHANGING PSYCHOTHERAPY - FROM DENOMINATION TO PROFESSION

In the meta-analysis ''Changing Psychotherapy'' by Grawe, Donati and B ernauer different psychotherapeutic methods are compared based upon pu blished therapy studies. Hereby the authors claim also to have proven with statistical methods that certain kinds of therapy are more effect ive than others. I show here that the descriptive and inductive method s used are not able to withstand a critical examination; they are inco rrect and in most cases even inadmissible. The results of my examinati on show that there are four points of critique: 1. The question of how effective a kind of therapy is, according to Grawe's criteria, depend s more on the number of variables and their measurements with which a therapy is judged than on the number of patients examined in the singl e studies. 2. Grawe does not distinguish between dependent and indepen dent variables or measurements; every measurement of each variable is included in his methods with the same weight. 3. The different effect variables used to evaluate the therapic process are mostly represented on varying ordinal scales which are incomparable with each other. Gra we treats these scales as if they were comparable, often even as if th ey were metric. 4. All five statistical methods (counting significance s, binomial test, profile of difference values, t-test, Wilcoxon-test) with which Grawe evaluates the results of the single studies are inad missable because the conditions required are not met. In sum: The conc lusions stated in the meta-analysis cannot be seen as being statistica lly validated or statistically proven.