Google Scholar tool gives extra credit to first and last authors

The h-index — a widely used measure of impact based on publications and citation count over time — treats all of an author’s papers equally, irrespective of whether they are a first, last or middle author. A browser extension called GScholarLens now aims to change that for Google Scholar users.

Launched earlier this year for the Google Chrome and Mozilla Firefox browsers, the tool provides a weighted metric, called the Scholar h-index (Sh-index), which accounts for a researcher’s position in author lists.

The tool gives corresponding (or last) authors the highest weighting: 100% of the citations that their paper accumulates contributed to their Sh-index. First authors receive the second-highest weighting, of 90% of the total citations.

Second authors get a 50% weighting. Other co-authors get 25% if there are six or fewer authors, or 10% if there are seven or more authors, according to a preprint published in September¹ by the tool’s creators.

The highest weighting is given to the first and last authors because, in most research fields, they are the people who contributed most to the paper, says GScholarLens co-creator Gaurav Sharma, a computational biologist at the Indian Institute of Technology Hyderabad in Kandi. He adds that the weighting given to authorship positions might be tweaked in the future on the basis of user feedback.

The Sh-index was designed to help researchers, institutions and policymakers to create fairer and more-comprehensive evaluation systems that capture the nuance of authorship, says Sharma.

For example, if a researcher is a co-author on a few very highly cited papers and first or last author on several less-cited papers, their h-index will be high, but their Sh-index will be low, which could give a more accurate picture of their work. “Overall, productivity-wise, contributions of such authors are mostly collaborative in nature, where they often support large teams but seldom lead small or big projects,” says Sharma.

A high h-index and low Sh-index could also help to identify individuals who might be engaging in unethical practices, such as gift or paid authorship — in which researchers become authors of papers without actually contributing to the work.

Capturing the nuance

Fair credit for contributions is a major challenge in academic publishing. In a 2022 survey of around 47,000 researchers across Europe, just under 70% said they’d worked on projects for which some authors hadn’t contributed enough to deserve credit.

Alberto Martín-Martín, an information scientist and bibliometrician at the University of Granada in Spain, says that he is sympathetic to the aims of GScholarLens. But he adds that he is not sure that the tool achieves its goal of making Google Scholar data more useful for research evaluation.

Simply assigning different weights to study authors isn’t enough to capture the nuances of their contributions, says Martín-Martín, because authorship positions themselves aren’t perfect representations of contributions. For example, two researchers might perform the same task in different projects, and one could be assigned a second-author position whereas the other becomes one of the co-authors. He also notes that GScholarLens wrongly assumes that corresponding authors are always last in author lists, which is often not the case.