Increasing interest in quality assurance and effectiveness in health care has been generated by three major things: about 20% of care is consistently demonstrated to be inappropriate, variations in practice cannot be explained by patient or facility factors, and decreased utilization as a result of changing economic and regulatory incentives seems to lead to both inappropriate care and appropriate care reduction. This interest has led to at least three changes in the approach to quality assurance. First, a move from measuring practitioner competence to measuring population health outcomes. Second, less use of implicit judgements and greater attention to explicit standards (e.g. practice guidelines) and explicit processes to establish the standards. Third, less organizational isolation of quality assurance and greater efforts to integrate it into everyday activities and across levels of health care delivery.