The sum of all the activities which create desired change in quality. In the health care setting, quality improvement requires a feedback loop which involves the identification of patterns of the care of patients (or of the performance of other systems involved in care), the analysis of those patterns in order to identify opportunities for improvement (or instances of departure from standards of care, and then action to improve the quality of care for future patients. An effective quality improvement system results in stepwise increases in quality of care. Quality control, with which quality improvement is sometimes confused, is the sum of all the activities which prevent unwanted change in quality.