Ben Goldacre, one of this blog's favorite journalists/authors/doctors/critics, has a fascinating new post up on his secondary blog. We all know that a journal's impact factor is largely useless for grading the quality of an individual paper. This follows from the old idiom, that you can't judge a book by it's cover. However, impact factors are also a poor way of comparing the quality of journals themselves. For one, journals that contain many review articles have higher impact factors since reviews are cited more frequently than original research. Journals game their impact scores by publishing more review articles. Now there is evidence that editors are gaming impact scores by forcing authors to cite articles from their journals before accepting the paper! Craziness.
The evidence from a revise and resubmit letter: “The Editors would also greatly appreciate you adding more than two but fewer than six references of articles published in [the Journal involved], above all articles published over the past two years.” Even more evidence that you can't judge a book by the cover.
I would write more, but I gotta go round, so I leave it to Mr. Bo Diddley...
(1) Ben Goldacre Secondary Blog - 16 January 2012
(2) F. Avanzini et al. Journal of Thrombosis and Haemostasis