[Development and test-theoretical analysis of an instrument for data collection on patients' preferences and experiences concerning participation in nursing care decisions in acute hospitals].

Patient orientation and patient participation are important aspects of modern health care and should be taken into consideration in the context of nursing care decision-making. The concept of evidence-based nursing also includes patient preferences in participation on decision-making, an area, however, which has not been adequately investigated so far. The aim of the present study was the development and testing of an instrument in German language for collecting data on patients' preferences and the experience of patients regarding their participation in nursing care decision-making in acute hospitals. The generation of items was based on available literature and in collaboration with specialists, using the theoretical model of Charles, Gafni and Whelan (1999). For testing the instrument, data was collected on 967 adult patients in surgical and medical wards of five hospitals in Vienna from October 2007 to March 2008. Test theoretical analyses included checking internal consistency, construct validity and criterion validity. The reliability of the scale preference and experience were confirmed by Cronbach's alpha (> or = 0.84) and the results of item analysis. The construct validity was supported by representing the decision model in the data. The criterion validity (concordant and discriminant validity) was tested with the two external criterions of subjective satisfaction with the information provided and decision making, and was supported by the results both at the level of total scores and at the level of item scores. In summary, the developed instrument represents an adequately reliable and valid test-theoretic, and also model-theoretic instrument for research in the field of evidence-based nursing. Therefore it is capable of gathering new knowledge on patients' preferences on participation in nursing care decision making.