Two new kids on the block: How do Crossref and Dimensions compare with Google Scholar, Microsoft Academic, Scopus and the Web of Science?

In the last 3 years, several new (free) sources for academic publication and citation data have joined the now well-established Google Scholar, complementing the two traditional commercial data sources: Scopus and the Web of Science. The most important of these new data sources are Microsoft Academic (2016), Crossref (2017) and Dimensions (2018). Whereas Microsoft Academic has received some attention from the bibliometric community, there are as yet very few studies that have investigated the coverage of Crossref or Dimensions. To address this gap, this brief letter assesses Crossref and Dimensions coverage in comparison to Google Scholar, Microsoft Academic, Scopus and the Web of Science through a detailed investigation of the full publication and citation record of a single academic, as well as six top journals in Business & Economics. Overall, this first small-scale study suggests that, when compared to Scopus and the Web of Science, Crossref and Dimensions have a similar or better coverage for both publications and citations, but a substantively lower coverage than Google Scholar and Microsoft Academic. If our findings can be confirmed by larger-scale studies, Crossref and Dimensions might serve as good alternatives to Scopus and the Web of Science for both literature reviews and citation analysis. However, Google Scholar and Microsoft Academic maintain their position as the most comprehensive free sources for publication and citation data.