Comparison of OpenAlex and Scopus coverage of German institutions' publications in top-tier journals

TL;DR

This study compares OpenAlex and Scopus in covering German institutions' publications, highlighting OpenAlex's broader journal coverage but lower institutional accuracy, and its suitability for relative rankings.

Contribution

It provides a systematic assessment of OpenAlex's affiliation data quality against Scopus for German research institutions in top-tier journals.

Findings

OpenAlex has broader journal coverage than Scopus.

Institutional publication counts are lower in OpenAlex.

High correlation suggests stable relative rankings.

Abstract

OpenAlex has recently emerged as a leading alternative to proprietary bibliometric sources. However, concerns remain regarding the quality of its metadata, especially the institutional profiles which are crucial for evaluating organizations. This study assesses the quality of affiliation data in OpenAlex using German research institutions. Publications from top-tier journals were analyzed and institutional publication counts in OpenAlex were systematically compared with counts in Scopus. The results show that OpenAlex generally contains more publications at the journal level, reflecting its broader coverage. However, institutional publication counts in OpenAlex are consistently lower, indicating missing or incorrectly assigned affiliations. Nevertheless, the correlations between institutional outputs in both databases are very high, suggesting that relative institutional rankings remain stable. These findings suggest that OpenAlex is suitable for comparative institutional analyses in academic research but requires further improvement in affiliation metadata before it can be used for evaluation contexts that rely on absolute publication counts.