Counting physicians: Inconsistencies in a commonly used source for workforce analysis

Purpose To assess the accuracy of the AMA Masterfile. Method In 2002, the authors compared the listing in the Masterfile for pediatric cardiologists with a roster of all such physicians documented by the American Board of Pediatrics (ABP) to have completed pediatric cardiology training. Physicians listed on the Masterfile but without ABP records of training completion received a mail survey. For main outcome measures, the differences in state-level distribution of pediatric cardiologists were used, depending on whether data were from the ABP or the AMA Masterfile. Survey items included nature and duration of medical training, the amount of time caring for pediatric or adult cardiology patients, and whether the respondent conducted echocardiograms and/or cardiac catheterizations on children and/or adults. Results Of the 2,675 unique, individual physicians obtained from the queries of both lists, 58% (1,558) were listed by both the Masterfile and the ABP. Another 28% (738) were listed by the AMA Masterfile only, and 4% (108) were listed by the ABP only. Of those listed by the Masterfile only, 40% reported they provide no pediatric cardiology care. The amount of pediatric cardiology training was highly variable among the remainder of the respondents. Conclusions There are large differences in the number and distribution of physicians identified as pediatric cardiologists between these two datasets. Also, many are potentially providing care for which they have little or no training. Use of such data has the potential to lead to policy options at odds with the actual needs of our nation as a whole or of specific geographic areas.