Which of the metadata with relevance for bibliometrics are the same and which are different when switching from Microsoft Academic Graph to OpenAlex?

Abstract

With the announcement of the retirement of Microsoft Academic Graph (MAG), the non-profit organization OurResearch announced that they would provide a similar resource under the name OpenAlex. Thus, we compare the metadata with relevance to bibliometric analyses of the latest MAG snapshot with an early OpenAlex snapshot. Practically all works from MAG were transferred to OpenAlex preserving their bibliographic data publication year, volume, first and last page, DOI as well as the number of references that are important ingredients of citation analysis. More than 90% of the MAG documents have equivalent document types in OpenAlex. Of the remaining ones, especially reclassifications to the OpenAlex document types journal-article and book-chapter seem to be correct and amount to more than 7%, so that the document type specifications have improved significantly from MAG to OpenAlex. As another item of bibliometric relevant metadata, we looked at the paper-based subject classification in MAG and in OpenAlex. We found significantly more documents with a subject classification assignment in OpenAlex than in MAG. On the first and second level, the classification structure is nearly identical. We present data on the subject reclassifications on both levels in tabular and graphical form. The assessment of the consequences of the abundant subject reclassifications on field-normalized bibliometric evaluations is not in the scope of the present paper. Apart from this open question, OpenAlex seems to be overall at least as suited for bibliometric analyses as MAG for publication years before 2021 or maybe even better because of the broader coverage of document type assignments.

Why are these publications missing? Uncovering the reasons behind the exclusion of documents in free‐access scholarly databases

“…However, in that moment, all the records came from MAG, we accordingly suppose that OpenAlex would not provide more information than the reported by MAG. A recent publication, testing differences between MAG and OpenAlex, showed that, in the early moments, OpenAlex was just a MAG mirror enriched with Crossref's DOIs (Scheidsteger & Haunschild, 2023), being in line with our preliminary results.…”

A Multiverse Analysis on the relationship between interdisciplinary research and scientific impact

“…Currently this method is expensive to develop and hard to evaluate, but there are several providers of ready-made semantic classifications of disciplines. This study uses the OpenAlex database (OA), which has large coverage and is easily available to the public through an API (Aria and Le, 2023;Scheidsteger and Haunschild, 2023;Velez-Estevez et al, 2023). OpenAlex consists of lists of five types of entities: works i.e.…”

How similar are field-normalized scores from different free or commercial databases calculated for large German universities?

“…Dimensions (Herzog, et al, 2020) has a two-level hierarchy of Fields of Research with 22 main categories and 154 sub categories. OpenAlex has a six-level hierarchy of concepts with 19 toplevel categories and 284 second-level categories (Scheidsteger & Haunschild, 2023). In the case of Dimensions and OpenAlex, we used the second-level (sub) categories for the fieldnormalization because of their similar granularity compared to the journal-based schemes.…”