[Methods for organisational health services research].

On 1 July 2009, the German Network for Health Services Research [Deutsches Netzwerk Versorgungsforschung e. V. (DNVF e. V.)] approved the Memorandum III "Methods for Health Services Research", supported by the member societies mentioned below and published in this journal (Gesundheitswesen 2009; 71: 505-510). The focus of this part of the Memorandum III "Methods for health services research" is on the questions and methods of organisational health services research. In a first step, we describe the central questions which are at the core of organisational health services research. In a second step, we describe the methodological standards and requirements with regard to a) sampling, b) measurement and c) research design. We present a phase model for complex intervention trials. This model allows to conduct high quality organisational health services research, to integrate different methods of social research and to show in which phase they are of special importance.