Scholars at Leiden University have conducted a large-scale document-level comparison of five major bibliographic data sources, with a specific focus on differences between the data sources in the coverage of documents and in the completeness and accuracy of citation links. That focus provides a useful comparison for others. The preprint, made available via arXiv and announced May 22, is entitled Large-scale comparison of bibliographic data sources; Scopus, Web of Science, Dimensions, Crossref and Microsoft Academic, was written by Martijn Visser, Nees Jan Van Eck and Ludo Waltman of the Centre for Science and Technology Studies of Leiden University.
Taken in pairs, Scopus is compared against the other four multidisciplinary resources by considering documents covered in the period of 2008-2017. The authors note in their conclusion that the key value points of these resources include coverage, the completeness and accuracy of the data collected, the speed and reliability of updates, and the available options and conditions offered for working with the data.
Among other findings, the authors documented the following:
- Microsoft Academic offers by far the most comprehensive coverage of the scientific literature, covering more documents than the other data sources. However, on the basis of its limited scope in identifying document type, they felt usage might be hindered.
- The two most long-established resources (Scopus and WOS) outperform more recent entrants to the field.
- Scopus covers a large number of documents not covered by Web of Science, including items with substantial numbers of references and citations. WOS covers meeting abstracts and book reviews, which are not covered by Scopus. A substantial share of the proceedings papers covered in WOS are not contained in Scopus.
- Dimensions relies heavily on data from CrossRef. Those sources cover a larger number of documents published in journals not covered by Scopus, including meeting abstracts and other short items.
Multiple graphs are included. Information professionals will find this in-depth study to be worthwhile reading.