[Individualized outcome measurement -- a comparison between prospective and retrospective problem marking in...

This article reports on a questionnaire concerning individual problems in psychosomatic rehabilitation. A sample of 858 patients answered the questions at the beginning and on a one year catamnestic measurement. First, the frequency of occurrence of several symptoms was asked. Second, the rehabilitants were asked to indicate for each symptom if it was an important problem before treatment. This procedure of identifying problems was done at the beginning (prospective marking) and also at the one year follow up (retrospective marking). The questionnaire allows to compute eight subscales and one global scale regarding all items (classical approach). Frequency of occurrence decreased with an average effect size (ES) of 0.56 on the global scale. In the next step, measurement was individualized by regarding only items which were marked as relevant problem. By prospective marking, effect size was 1.32. By retrospective marking, no growth of effect size in comparison to the classical approach was found (ES = 0.56). The results indicate that the prospective approach of identifying problems is the better way of individualizing measurements. Moreover, the impact of individual problem definition on outcome was demonstrated.