Non-cumulative measures of researcher citation impact

TL;DR

This paper investigates non-cumulative citation impact measures for researchers, proposing new metrics based on citation acceleration, with theoretical justification and promising initial results for assessing recent research impact.

Contribution

It introduces novel non-cumulative citation impact measures, including citation acceleration, and provides theoretical foundations and initial empirical evaluation.

Findings

New measures outperform traditional cumulative metrics in recent impact assessment

One proposed measure has strong theoretical justification

Initial data shows promising results for future research use

Abstract

The most commonly used publication metrics for individual researchers are the 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 non-cumulative 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 non-cumulative 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.