A modification of the h-index: the hm-index accounts for multi-authored manuscripts

TL;DR

This paper introduces the hm-index, a modified h-index that accounts for multi-authored papers through fractional counting, and demonstrates its advantages over other variants.

Contribution

It proposes the hm-index as a new metric for evaluating scientific impact that better accounts for co-authorship, improving upon existing fractional and normalized h-index variants.

Findings

hm-index outperforms fractional citation counting

hm-index is superior to average-author normalization

Empirical and model cases validate the effectiveness of the hm-index

Abstract

In order to take multiple co-authorship appropriately into account, a straightforward modification of the Hirsch index was recently proposed. Fractionalised counting of the papers yields an appropriate measure which is called the hm-index. The effect of this procedure is compared in the present work with other variants of the h-index and found to be superior to the fractionalised counting of citations and to the normalization of the h-index with the average number of authors in the h-core. Three fictitious examples for model cases and one empirical case are analysed.