RT Journal Article SR Electronic T1 The ABFM Begins to Use Differential Item Functioning JF The Journal of the American Board of Family Medicine JO J Am Board Fam Med FD American Board of Family Medicine SP 807 OP 809 DO 10.3122/jabfm.2013.06.130239 VO 26 IS 6 A1 O'Neill, Thomas R. A1 Peabody, Michael R. A1 Puffer, James C. YR 2013 UL http://www.jabfm.org/content/26/6/807.abstract AB