Predicting impact factor one year in advance

The first impact factor (IF) to reflect the sole efforts of a new editorial team occurs 4 years into what is usually a 5-year editorship, owing to the lag times of: paper accrual and publication, accumulation of citations in derivative literature, and compiling of such citations by the Thomson ISI Web of Knowledge service. Through weekly collection of citation data from the Web of Science over the past 2 years, we now demonstrate that the evolution of IF can be tracked weekly over the course of a calendar year, enabling prediction of the next year's IF beginning at the middle of the previous year. The methodology used to track the developing IF for Lab Invest is presented in this study and a prediction made for the 2006 IF, along with IF predictions for other general pathology journals (American Journal of Pathology, Journal of Pathology, Modern Pathology, American Journal of Surgical Pathology, and Human Pathology). Despite the fact that the 2006 IF for Lab Invest will not be issued until June 2007, it became apparent as early as July 2006 that the Lab Invest IF would be greatly improved over 2004 and 2005 by a predicted 0.5 units. However, as important as IF can be to a journal, it is vital not to let IF considerations influence every aspect of the editors' decisions. Rather, the significance of early prediction lies in earlier validation of editorial policies for journal management as a whole, and reassurance that the philosophy for journal operations is on track.