Since Alison Glover’s classic 1938 study showing local differences in rates of tonsillectomy among British schoolchildren,1 health service researchers have documented extensive variation in the delivery of healthcare in many parts of the world.2 3 4 5 Information on practice variation is important for examining the relations between policy decisions and clinical decisions and raises important questions concerning the efficiency and effectiveness of healthcare. I have therefore argued that population based information should be routinely reported6 and, through the Dartmouth Atlas Project, have taken steps to make such information publicly available for care to Americans aged ≥65 years provided through the Medicare programme. The project has highlighted that much of the variation among hospital referral regions in per capita spending, resource allocation, and service use is unwarranted because it isn’t explained by illness or patient preference.7 8

The publication of The NHS Atlas of Variation in Healthcare,9 which compares healthcare delivery among primary care trusts, shows a similar story in England. Below, I consider the relevance of the Dartmouth work for the NHS.