Guides: Altmetrics, Bibliometrics and Scholarly Impact: Traditional Bibliometrics

Journal Impact Factor

Journal Impact Factor is a journal-level metric rather than article-level. According to Clarivate Analytics, the impact factor of a journal is calculated by dividing the number of current year citations to the source items published in that journal during the previous two years (see Figure 1). You can find the impact factor of a journal by searching the Journal Citation Reports database located within the Web of Science platform. A related metric is SJR (SCImago Journal Ranking) which measures journals by the number of citations they receive and the importance of the journals from which the citations originate. You can access SJR data from a freely available portal on the web.

Source Normalized Impact per Paper (SNIP) is a sophisticated metric that intrinsically accounts for field-specific differences in citation practices. It does so by comparing each journal’s citations per publication with the citation potential of its field, defined as the set of publications citing that journal. SNIP therefore measures contextual citation impact and enables direct comparison of journals in different subject fields, since the value of a single citation is greater for journals in fields where citations are less likely, and vice versa. SNIP is calculated annually from Scopus data and is freely available alongside CiteScore and SJR at www.scopus.com/sources.

Author H-Index

Unlike Journal Impact Factor which calculates scholarly significance of journals, the H-Index measures scholarly impact of an individual author's work. The H-Index measure both the number of publications of an author and the number of citations of the publications. It is equivalent to the number of citations that are equal to or greater than the number of papers. For example, an H-Index of 5 would mean that an author has published five papers each of which has been cited at least five times. You can find your H-Index by searching in Web of Science, Scopus, or Google Scholar. The H-Index may vary in each of these sources because they index different publications. The famous scientist Stephen Hawking has an H-Index of 72 in Scopus, 76 in Web of Science, and 130 in Google Scholar. This is because Google Scholar includes a much broader universe of publications than Scopus or Web of Science.

Comparing Bibliometrics and Altmetrics

Interestingly, the misspelling in the title raises the question whether "altmetrics" might better be referred to as "allmetrics" because bibliometrics and altmetrics can be seen as complimentary rather than in opposition. Using both may provide a more complete picture of an author's scholarly influence than either alone could provide.