Claims analysis and efficacy study are 2 new methods of evaluating medical services. In Manitoba [Canada], with a 1974 population of 1,053,382 approximately 100,000 patient-physician interfaces resulted in 16,594 Ba enema examinations; 1000 significant abnormalities were discovered and the referring physician was unusually perceptive in predicting the likelihood of these abnormalities. It was estimated that a 10% reduction in use of Ba enemas could be achieved by referring physicians with no deterioration in patient care.