Analysis of the Publication and Document Types in OpenAlex, Web of Science, Scopus, PubMed and Semantic Scholar

The assignment of document and publication types in scholarly databases plays an important role in bibliometrics, for example in decision-making or university rankings. However, scholarly databases apply different curation strategies and taxonomies when classifying documents which makes it difficult to compare results from different database providers. In this study, the bibliometric databases OpenAlex, Web of Science, Scopus, PubMed and Semantic Scholar are used to analyse the extent of data variation and compare different approaches to taxonomy and data curation. Using a shared corpus of 9,575,603 publications from 2012 to 2022, we found large differences in the classification of document types such as research articles and editorials in these databases. We can also show that many of the records that lack a publication type in OpenAlex are classified as conference proceedings in Scopus and Semantic Scholar.