CONTEXT Certification by an American Board of Medical Specialties (ABMS) member board is emerging as a measure of physician quality.   
 OBJECTIVE To identify demographic and educational factors associated with ABMS member board certification of US medical school graduates.   
 DESIGN, SETTING, AND PARTICIPANTS Retrospective study of a national cohort of 1997-2000 US medical school graduates, grouped by specialty choice at graduation and followed up through March 2, 2009. In separate multivariable logistic regression models for each specialty category, factors associated with ABMS member board certification were identified.   
 MAIN OUTCOME MEASURE ABMS member board certification.   
 RESULTS Of 42,440 graduates in the study sample, 37,054 (87.3%) were board certified. Graduates in all specialty categories with first-attempt passing scores in the highest tertile (vs first-attempt failing scores) on US Medical Licensing Examination Step 2 Clinical Knowledge were more likely to be board certified; adjusted odds ratios (AORs) varied by specialty category, with the lowest odds for emergency medicine (87.4% vs 73.6%; AOR, 1.82; 95% CI, 1.03-3.20) and highest odds for radiology (98.1% vs 74.9%; AOR, 13.19; 95% CI, 5.55-31.32). In each specialty category except family medicine, graduates self-identified as underrepresented racial/ethnic minorities (vs white) were less likely to be board certified, ranging from 83.5% vs 95.6% in the pediatrics category (AOR, 0.44; 95% CI, 0.33-0.58) to 71.5% vs 83.7% in the other nongeneralist specialties category (AOR, 0.79; 95% CI, 0.64-0.96). With each $50,000 unit increase in debt (vs no debt), graduates choosing obstetrics/gynecology were less likely to be board certified (AOR, 0.89; 95% CI, 0.83-0.96), and graduates choosing family medicine were more likely to be board certified (AOR, 1.13; 95% CI, 1.01-1.26).   
 CONCLUSION Demographic and educational factors were associated with board certification among US medical school graduates in every specialty category examined; findings varied among specialty categories.
True