In our article entitled “The Political Science 400: A 20-Year Update”(PS, January 2007, 133–45), we presented thenames and total citation counts (1960–2005) of political sciencefaculty employed (ca. 2002) in U.S. Ph.D.-granting institutions whowere among the 400 most cited in their cohort or subfield. Werecognize the very important nature of our data for individualscholars and the institutions at which they teach, and we apologizeto those colleagues whose citation counts were misreported,especially to those few whose counts were off by a very largeamount. Yet, given that nearly 4,000 political scientists areemployed in a Ph.D.-granting institution in the U.S., and given thenumerous data limitations associated with using the Web of Sciencesearch engine (as we explained in the lengthy methodologicalappendix to our article), while we worked as hard as we could toprevent errors, having some errors in our data set was virtuallyunavoidable.