[Evaluation of quality assurance--current data and consequences for research].

The number of voluntary and compulsory quality assurance programs has been continuously increasing in all sectors of the healthcare system for many years, on both national and international levels. Based on a current, comprehensive analysis of the literature, however, the evidence of their efficacy and efficiency is limited at this time; even though positive impacts for quality management and quality assurance measures, especially on performance processes, are reported, the impact on outcomes has not been proven or has been insufficiently demonstrated up to now, and the data must be evaluated, overall, as "consistently inconsistent". Based on this evaluation, causes for the lack of evidence and the high variability of the results are first outlined, which are especially inherent in the complexity and heterogeneity of the analyzed interventions. Building on this, the implications for future evaluations of quality management and quality assurance measures are then inferred.