Introducing fees for services with professional uncertainty.

A change in payment system of general practitioners from capitation to a mix of one-half capitation and one-half fee for service in Copenhagen, Denmark, resulted in a significant overall increase in diagnostic and curative services. The rate of increase differs between services. In this article, it is assumed that the rate of increase varies with doctors' professional uncertainty relative to the services studied. Professional uncertainty is measured as the degree to which performances of a service are determined by diagnoses made. The data validate the measure given the assumption.