Quality assurance in a cooperative group.

Quality control in a large cooperative group involves a number of different levels of checking which can be divided into three main sections: quality control in data management, quality control in special areas, and the verification that events on paper reflect real events in the clinic. Quality control in special areas is the province of those using various techniques and disciplines and it will not be discussed in this overview, since others will cover the monitoring of radiation therapy, standardization of biochemical tests, and pathology review.