Noncumulative measures of researcher citation impact

Abstract

The most commonly used publication metrics for individual researchers are the total number of publications, the total number of citations, and Hirsch’s h-index. Each of these is cumulative, and hence increases throughout a researcher’s career, making it less suitable for evaluation of junior researchers or assessing recent impact. Most other author-level measures in the literature share this cumulative property. By contrast, we aim to study noncumulative measures that answer the question “In terms of citation impact, what have you done lately?” We single out six measures from the rather sparse literature, including Hirsch’s m-index, a time-scaled version of the h-index. We introduce new measures based on the idea of “citation acceleration.” After presenting several axioms for noncumulative measures, we conclude that one of our new measures has much better theoretical justification. We present a small-scale study of its performance on real data and conclude that it shows substantial promise for future use.