Our new impact factor—3.53*

Why the asterisk? Our new “official” 2008 impact factor from Thomson Reuters is 2.83. It is wrong. As many of you know calculating the impact factor is not complicated—it is the number of citations in the literature to articles published in a journal over a defined period of time divided by the number of “substantive articles” over a two-year period. Despite our best efforts to ensure an accurate count of our denominator by Thomson it has made an error. We do not dispute the number of citations (1352) or to be more specific we did not check, but its denominator of 237 substantive publications in 2006 and 240 in 2007 is wrong. Unfortunately, it counted Perspectives, Archimedes, and a handfull of images and case reports, as substantive articles. Perspectives is not included in the denominator for NEJM, so why is it for ADC? In correspondence with Thomson in March 2009 it agreed to exclude Archimedes from the denominator. Why did that not happen? When I hand tallied original and short reports, and leading articles and reviews, my count for those two years is 188 and 195. Hence I calculate our 2008 …