Over at A Blog Around the Clock, Coturnix has a post on a recent editorial that calls into question the way impact factors are calculated. The editorial, published in the Journal of Cell Biology and penned by heads of that publication, the Journal of Experimental Medicine, and Rockefeller University Press, says that a number of subjective factors affect the calculations, such as publishers' ability to negotiate for better rankings. Blogger Coturnix says, "Apparently, it is really a magic number calculated in a mysterious way, not in the way that [Thomson] Scientific claims they do it."
Still, GTO would love to see a source for this that didn't have a connection to the very journals being affected by the impact factor process. Surely some unaffiliated number-crunchers would be interested in performing the audit?