Diagnostic radiologists' subspecialization and the new final board examination

Recognizing that subspecialization can consist of concentration in multiple fields as well as in a single main field, we conducted this study to profile in detail the subspecialization of diagnostic radiologists in the United States in ways that illuminate issues related to the American Board of Radiology plan for a new final examination.

We tabulated nonindividually identified data from the American College of Radiology 2003 Survey of Radiologists, a stratified random-sample mail survey with 1,924 responses and a 63% response rate. Respondents were guaranteed confidentiality. Responses were weighted to make them representative of all radiologists in the United States.

Sixty-nine percent of respondents reported specializing at least to a small extent. If concentration in a field is defined as spending 10% or more of clinical work time in the field, 51% of radiologists concentrated in one or two fields, 24% in three or four fields, and 21% in more than four fields. An examination covering a radiologist's four most time-intensive fields would cover 80% of the clinical work of the median radiologist. However, the one fourth of radiologists whose work is most varied would have 40% or more not covered by the examination, but the one fourth with the most concentrated work would have 100% covered.

Most radiologists concentrate in a few fields, making the American Board of Radiology plan for an examination that covers four fields--or fewer, at an examinee's discretion--a major step forward in recognizing the nature of current practice. Four fields, however, are too many for the practice patterns of many radiologists but too few for the practice patterns of a substantial minority. We offer for consideration more far-reaching reforms.