A Relative Authorship Index: A New Metric for Evaluating Individual Contribution in Scientific Research

TL;DR

The paper introduces a new metric called the relative authorship index to better evaluate individual contributions in scientific research by accounting for authorship inflation.

Contribution

The novel contribution is the development of the relative authorship index (RAI) to correct for inflated authorship in bibliometric evaluations.

Findings

The RAI revealed significant regional and institutional differences in authorship practices in Italian universities.

A temporal analysis showed a steady upward trend in RAI over time, with a slight decline around 2010.

The proposed authorship correction formula penalizes inflated authorship and large co-author counts based on RAI.

Abstract

This study presents the relative authorship index (RAI), a novel metric designed to address the limitations of traditional bibliometric indicators, such as publication counts, citation numbers, and the h‐index, by correcting for authorship inflation. Conventional metrics can overestimate productivity by failing to account for the number of co‐authors or the possibility of inflated authorship. To detect such inflation, this index evaluates the number of co‐authors on a paper relative to the number of authors in the references cited within the same paper, which are assumed to reflect the researcher's specific field of study. By using this field‐specific baseline, the index identifies whether a publication involves an unusually high number of co‐authors compared to field standards, thus flagging potential authorship inflation. Applied to neuroscience articles authored by researchers affiliated with Italian universities, the index revealed significant regional and university differences, with higher values in southern regions and private universities. A case study of a single department also revealed high variability among individual researchers, indicating that the index can capture consistent patterns in authorship practices. In addition, we propose an authorship correction formula to adjust bibliometric indicators. The formula introduces parameters that penalize authorship inflation based on the RAI and also penalize large co‐author counts, with the latter scaled according to whether the researcher occupies key authorship positions (first, last, and/or corresponding author).

This study introduces the relative authorship index (RAI) to assess individual contributions by correcting for authorship inflation. Analysis of the Italian academic landscape reveals that RAI is significantly lower in northern universities compared to central and southern institutions and lower in public versus private universities. Furthermore, a temporal analysis (sampled every 3 years) shows a steady upward trend in RAI over time, despite a slight decline around 2010, reflecting shifting collaborative patterns in scientific research.

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