An evaluation of the American Medical Association's Physician masterfile as a data source--one state's experience.

An evaluation of the American Medical Association's (AMA) Physician Masterfile is presented here on a state level. Both completeness and reliability of the AMA data were assessed for physicians licensed and living in Washington State. Comparison of the AMA data with state -LICENsure data indicated excellent agreement, with only a small proportion of license physicians "missing" from the AMA Masterfile. Their absence was due largely to differences in the manner in which the two systems updated their files. The reliability of the AMA data was checked by comparing it with similar, independently gathered survey data on birth date, birthplace, medical school, type of practice, specialty, board certifications, and employer. In general, despite some minor deficiencies, the AMA data were shown to be highly reliable.