This project will involve analysis of the economic incentives that face surgeons as advisors and providers of the service, and patients, identifying necessary market conditions, and institutions that ensure efficient provision of the service. It will involve artefactual field experiments using a two-sided survey with surgeons and patients to study the determinants and institutions governing surgeons’ recommendations and patient decisions. The survey will vary between surgeons with respect to the availability of information about the different procedures, the economic incentives and the description of the simulated patient. Surgeons will be asked to make recommendations based on anonymised patient cases, which will be compared against best practice as determined by an expert panel and observed behaviours.