[Questionnaire of self-efficacy, optimism and pessimism: reconstruction, selection of items and validation of an instrument by means of examinations of clinical samples].

Self-efficacy and optimism are considered highly useful parameters in the context of therapeutic indication prognosis, and outcome evaluation. In our study, a combined questionnaire measuring "self-efficacy" (Schwarzer u. Jerusalem 1986) and "optimism" (Scheier u. Carver 1985) was restructured and reduced in length. The resulting instrument was compared with its original version in five different clinical samples comprising n = 726 inpatients. Factor analyses achieved the bidimensionality in the construct "optimism" as postulated by Scheier and Carver, this yielding the two factors "optimism" and "pessimism". The statistical validation resulted in good to optimal values. Factor analyses considering the different clinical groups showed that certain items failed to be invariably approprieted to one factor. Therefore, we decided in favor of an item reduction, resulting in half the original number: 5 items representing "self-efficacy" 2 for "optimism" and 2 for "pessimism". The scale values of the reduced version showed no relevant deviations compared to the original, and hence we conclude that the reduction does not result in a loss of information.