Practice variation and the complexity of medical decisions

The first systematic account of practice variation was Glover’s 1938 report on the incidence of tonsillectomy among schoolchildren in England and Wales.4 He found a tenfold variation in tonsillectomy rates from one region to another. Although he did not comment on the economic consequences of this variation, he did observe that for every death caused by complications attributable to enlarged tonsils there were at least eight deaths caused by tonsillectomy. Economics aside, there was a clear ethical imperative to question and confront practice variation.

Decades after Glover’s report, regional variations in tonsillectomy and other surgical procedures were rediscovered in the United States (figure⇓).1 2 5 Wennberg and colleagues showed that, although the incidences of their studied surgical procedures often varied between countries, the degree of variation within countries for each procedure was similar. Furthermore, the degree of variation was associated with the level of uncertainty about the probabilities of surgical outcomes.5