Reliable quality data are an important basis for attempts to improve quality and safety of patient care. For anesthetic practice in Switzerland, an "Absolute Minimal Data Set" (AMDS) of preoperative patient characteristics and intra- and postoperative quality indicators is provided by the Institute of Social and Preventive Medicine (IUMSP, University of Lausanne) in cooperation with the Swiss Society of Anaesthesiology and Reanimation (SGAR-SSAR). Data are electronically forwarded by the participating institutions to IUMSP, whereas primary collection can be achieved by traditional paper records or electronic records as part of anesthesia information management systems (AIMS).