The article analyses the challenges of previous quality assurance efforts in the field of psychiatric and psychotherapeutic care in Germany. Despite the high level of healthcare expenditure in Germany, the country only achieves average results in health-related indicators. Moreover, initiatives to measure treatment quality often fail due to insufficient data quality and availability. The discussion focuses on 2 central problems: the vague definition of needs-based care and the limited applicability of evidence-based guidelines for quality measurement. Finally, the guideline on staffing levels for inpatient psychiatric and psychosomatic facilities (Richtlinie zur Personalausstattung für stationäre Einrichtungen in der Psychiatrie und Psychosomatik, PPP-RL) is discussed as a quality assurance instrument.