The first steps in quality assessment of results of performance in gynecology and obstetrics were taken by the Swiss Association of the OB/GYN Clinics of the Swiss Society of Obstetrics and Gynecology in the 1980's. Currently, medical data of more than 800,000 patients are available, allowing a good comparison of the quality of results. Concerned that purchasing coverage for health services was made exclusively on the basis of cost, resulting in lower public health quality, the Swiss Society of OB/GYN set up a Board of Quality Assessment in 1995. Not only the quality of results, but also the quality of indications, structures and processes are considered by using a modified Donabedian model. Moreover, standardized patient information forms have been worked out for 15 gynecological and five obstetrical operations. Since hysterectomy is the most common major gynecological operation in Switzerland, the evaluation of the quality of the indications is of substantial interest. Guided by the RAND Appropriateness Method, criteria for quality assessment with respect to appropriateness and necessity of hysterectomy have been drawn up. Swiss guidelines and 125 different clinical scenarios are defined by a panel of 22 OB/GYN experts. The aim of this project is to offer an interactive second opinion system, called "Swiss Guidelines for Hysterectomy", and anonymous self-assessment of quality. Appropriateness and necessity of medical procedures have to be defined by medical professionals providing a proper balance between the patient's desires and financial demands.