Numerators and denominators of rates estimated on the basis of physicians' practice data

The paper discusses selected methodological aspects of numerators and denominators derived from medical practice observations. The estimation of rates (of incidence or prevalence) on the basis of primary care practice data is apt to be influenced by several methodological factors. These are: morbidity of the local population, physician workload and expertise, diagnosis coding rules, and patient visiting behavior (Anderson, 1984). These factors tend to have an impact on the numerator. Vis-à-vis the lack of appropriate population denominators of single practices, the question is whether rate estimates may be developed for fee-for-service systems without population registration of persons with medical practices and which use these rates may be put to.