The influence of dispersion on journal impact measures

Abstract

A family of measures of a journal’s impact is considered that takes account of the dispersion, as well as the mean, of the number of citations in a journal. These measures, called the Mean Dispersion Indices (MDI), generalize the stabilized-JIF recently introduced by Lando and Bertoli-Barsotti (J Informetr 11(3):689–703, 2017). The MDI use a geometric weighted average of the number of citations and the Gini coefficient to measure the dispersion of the number of citations. Journal rankings based on these measures are compared with those obtained from the Journal Impact Factor, the Scimago Journal Rank, the h-index measure, and the Eigenfactor rankings, four of the most well-known current impact measures. This comparison suggests that the different rankings may implicitly place different weights on dispersion and the average number of citations and some appear to show little correlation with dispersion.