Alice Steiner and Tanya Harden
Bibliometrics is the quantitative analysis of books, journals and other publications. Originally used as a collection development tool, it has now become part of research assessment exercises. Bibliometric measures, such as citations, are used to assess the reach or ‘impact’ of research publications, researchers and institutions. Metrics are available at an article-level, author-level and journal-level.
Article-level metrics measure the reach of individual publications and can include citations, field-weighted citation impact and category-normalized citation impact. Article-level metrics are increasingly being made available on publisher’s websites, in databases and citation indexes and in institutional repositories. Altmetrics, or alternative metrics, are also article-level metrics. These include mentions in both mainstream and social media, views and other measures. Altmetrics will be explored in more detail in a later chapter.
Exercise: Read the publication Article-Level Metrics to get an overview of article-level metrics. While at the publisher’s website, find the article-level metrics available for this article. What types of metrics have been supplied and where have they been sourced from?
Author-level metrics measure the scholarly impact of an individual researcher’s publication output. They include publication output, citations to the researcher’s publications and h-index. Some article-level metrics can be used at an author level, usually by calculating the average for that metric across an author’s publication output.
The h-index is one most well known author-level metrics is the h-index. It is calculated by counting the number of publications for which an author has been cited at least that same number of time. It attempts to measure a researcher’s productivity and impact. An author’s h-index can be easily found on their profile pages in tools such as Google Scholar, Scopus and Publons. Read the h-index page on the Metrics Toolkit website to find more information about the h-index, including appropriate and inappropriate use cases and limitations.
The h5-index is the h-index, calculated using a 5-year publication window.
The g-index gives more weight to highly-cited publications. See Wikipedia for an explanation of how it is calculate.
The i10-index the number of publications with at least 10 citations
Exercise: Go to Google Scholar and search for a researcher at your institution and click on Google Scholar Citations profile. What is their h-index?
Journal-level metrics aim to quantify the reach, impact and prestige of a journal. There are a number of journal-level metrics, including Journal Impact Factor (JIF), Scimago Journal Rank (SJR), CiteScore and Source Normalized Impact per Paper (SNIP). Journal-level metrics are the basis for a number of journal rankings, as described below.
The Journal Impact Factor (JIF) is a Clarivate Web of Science metric and in Journal Citation Reports (JCR), a subscription-based database. A journal’s impact factor is calculated by dividing the number of times articles were cited by the number of citable articles in a journal for a two-year period. Journals in JCR are allocated to different subject categories and allocated to quartiles within the category.
Scimago Journal Rank (SJR) is another journal-level metric and expresses the average number of weighted citations received in a selected year by the documents published in that journal in the previous three years. Scimago Journal Rank is based on Scopus data. Journals are allocated to different subject categories and allocated to quartiles within the category.
Source Normalized Impact per Paper is a metric developed by CWTS. It is calculated as the number of citations given in the present year to publications in the past three years divided by the total number of publications in the past three years. Citations are normalised to account for differences in citing behaviour in different disciplines. It is based on Scopus data. Journals are allocated to different subject categories.
CitesScore is calculated by dividing the number of citations to documents (articles, reviews, conference papers, book chapters, and data papers) by a journal over four years, by the number of the same document types indexed in Scopus and published in the same four years. Journals are allocated to different subject categories and allocated to quartiles within the category.
Exercise: Go to the CWTS Journal Indicators website. Filter by a subject area of your choice and then order by SNIP. What is the top-ranked journal in your chosen subject area?
There are a number of tools, both free and subscription-based, that are available to assist in biblibiometric analyses. Citation indices, which record the citations between publications are the basis for citation analysis, and their data is used to power more complex research analytics tools, which will be discussed in more detail in the Benchmarking chapter. Commonly used citation indices are:
The metrics available vary depending upon the index you are using.
AIRS Module 11: Publication metrics provides information from a higher research degree student’s perspective.
Information for QUT research staff about research metrics is available on the QUT Publication Metrics LibGuide.
Exercise: Google Scholar versus Web of Science and Scopus.
Consider: Read this blog post Google Scholar, Web of Science, and Scopus: Which is best for me?
The Initiative for Open Citations (I4OC) advocates for citation data to be made open. The citation data should be:
Consider: Read A tipping point for open citation data by B. Ian Hutchins. What are the reasons that the author believes that citation data will continue to be made freely available? What are the benefits of open citations?
There are a number of citation indexes and tools that are freely available including:
Exercise: Watch this video to learn how to search for an author in The Lens. Search for an author. What information is available, including metrics?
Content in this chapter has been developed by QUT Library, including content derived from:
All information correct at time of publication, 4 March 2021.
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