Comparison of OpenAlex and Scopus coverage of German institutions' publications in top-tier journals
For bibliometricians and research evaluators, this study validates OpenAlex's utility for relative institutional comparisons while highlighting its limitations for absolute metrics.
OpenAlex has broader journal-level coverage than Scopus but consistently lower institutional publication counts for German institutions due to missing or incorrect affiliations. Despite this, institutional rankings are highly correlated, making OpenAlex suitable for comparative analyses but not for absolute counts.
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.