Achieving equal standards in medical student education: is a national exit examination the answer?

To the Editor: The recent article by Koczwara and colleagues proposing a national exit examination for medical students1 prompted me to recall a 1970 trial of a national examination in surgery.2 Seven of the then eight medical schools participated. Interstate differences were wide for some questions; separate analyses of the 15 teaching hospitals showed variation to be even wider within a university than between universities. Do local differences still undermine the validity of a national examination?