A further step forward in measuring journals' scientific prestige: The SJR2 indicator

TL;DR

This paper introduces the SJR2 indicator, a size-independent measure of journal prestige that accounts for citation quality and proximity, improving upon existing metrics by reducing size bias and better reflecting thematic closeness.

Contribution

The paper proposes the SJR2 indicator, incorporating cosine similarity of cocitation profiles, and demonstrates its advantages over JIF and SNIP using the Scopus 2008 dataset.

Findings

SJR2 fits a logarithmic distribution similar to other metrics.

SJR2 shows major rank changes compared to JIF and SNIP.

SJR2 is more evenly distributed across subject areas, especially at lower levels.

Abstract

A new size-independent indicator of scientific journal prestige, the SJR2 indicator, is proposed. This indicator takes into account not only the prestige of the citing scientific journal but also its closeness to the cited journal using the cosine of the angle between the vectors of the two journals' cocitation profiles. To eliminate the size effect, the accumulated prestige is divided by the fraction of the journal's citable documents, thus eliminating the decreasing tendency of this type of indicator and giving meaning to the scores. Its method of computation is described, and the results of its implementation on the Scopus 2008 dataset is compared with those of an ad hoc Journal Impact Factor, JIF(3y), and SNIP, the comparison being made both overall and within specific scientific areas. All three, the SJR2 indicator, the SNIP indicator and the JIF distributions, were found to fit well to a logarithmic law. Although the three metrics were strongly correlated, there were major changes in rank. In addition, the SJR2 was distributed more equalized than the JIF by Subject Area and almost as equalized as the SNIP, and better than both at the lower level of Specific Subject Areas. The incorporation of the cosine increased the values of the flows of prestige between thematically close journals.