Increasing the between-year stability of the impact factor in the science citation index

The critical evaluation of scientific productivity during last years has been done with the help of the Journal Citation Reports ranks of journals. The relative performance of each journal was derived from a simple calculation called Impact Factor. Such measure has been widely criticized by scientometricians, but alternative proposals were never adopted due perhaps to their complexity, but also to economic limitations. For the informetric purposes this situation has led to a worrying lack of standardization and, worst of all, makes useless many studies for comparative purposes. In order to enhance the comparative value of the impact factor we develop a new easy method that increases the time period used for its calculation. Such new index has advantages over the old one.