Much of the evidence said to support the theory that radiology subspecialists make fewer mistakes than their generalist colleagues is anecdotal. The content of some peer-reviewed papers, however, appears to lend more credence to the theory. The results of a 2002 study¹ published in Radiology demonstrated a 76% higher cancer-detection rate for screening mammograms read by subspecialists than for those read by general radiologists. The study also showed, for screening mammography, that subspecialists’ early cancer-detection rate was approximately 77% higher than that of general radiologists. Moreover, in a 2007 article² in Clinical Radiology that compared neuroradiologists’ second-opinion reports for CT and MRI exams with general radiologists’ original interpretations, the authors found a 34% discrepancy rate. They concluded, “There is a significant major discrepancy rate between specialist neuroradiology second opinion and general radiologists. The benefit of a specialist second-opinion service is clearly demonstrated.” In the typical practice setting, however, most subspecialists do not exclusively read in their subspecialties, posing the following question: Do subspecialists, when reading outside their subspecialties, make a smaller or greater number of mistakes than general radiologists make?