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Citation Research and Impact Metrics

Methods and metrics for evaluating scholarly and research impact.

Introduction to Journal Assessment

Journal rankings typically use citation data to assess the quality of a given journal. The most well-known journal ranking system is the Journal Impact Factor (JIF), which is produced from citation counts collected from the Web of Science database. Other systems have been developed more recently, including Eigenfactor, Scimago Journal Ranking (SJR), Source Normalized Impact per Paper (SNIP), and SCOPUS CiteScore.

In this section, we focus on SCOPUS CiteScore and the Journal Impact Factor, however, we also have a brief explanation of other journal rankings.

Important Points:

  • Journal rankings are commonly misunderstood and frequently misused.
  • Journal rankings evaluate the performance of a journal as a whole but say nothing about the impact or quality of an individual article within the journal. Publication in a highly ranked journal does not guarantee an article will have impact, nor does publication in a low ranked journal indicate the absence of impact. Consequently, journal rankings should not be used to assess an author's publication packet nor an article's impact as the rankings measure neither author nor article performance.

Best Uses:

  • Journal rankings were originally intended to help librarians determine what journals should be in their collections and for editors to compare their journal's performance to others in the same field. These remain acceptable uses for journal rankings.
  • Journal rankings also help researchers find appropriate places for submitting their articles, although researchers should also consider such things as the journal's subject content, readership, and open access/open data policies. (See Getting Published)

The Journal Impact Factor

Please note that as of January 1, 2021 ASU Library has ended its subscription to Web of Science and Journal Citation Reports.

The Journal Impact Factor (JIF), using citation data from the Web of Science database (provided by Clarivate Analytics), is the original journal ranking product. JIF is a measure reflecting the annual average number of citations to recent articles published in a given journal. The full JIF information is found in the Journal Citation Reports (JCR) database which also includes Eigenfactor rankings and a five-year JIF. Selected JIF information can also be found directly in the Web of Science database. For a discussion of some of the issues associated with the JIF, please see the article below.

SCOPUS CiteScore

CiteScore is a product from Elsevier, using citation data from the Scopus database to rank journals. As with other journal ranking metrics, to compare journals across disciplines requires a "normalized" ranking, which CiteScore provides as a percentile ranking within the journal's subject category. In addition to the CiteScore number and percentile ranking, CiteScore also includes the SJR (Scimago Journal Rank) and SNIP (Source Normalized Impact per Paper) numbers.

Important Points:

  • Because the CiteScore is based on raw citations counts, comparing CiteScores in different disciplines penalizes journals in fields with naturally low citation numbers.
  • CiteScore may assign journals to more than one subject category. Additionally, the selected subject category for CiteScore in some cases has been either incorrect or questionable.
  • To compare journals across subject areas, CiteScore provides a CiteScore Percentile which normalizes the raw CiteScore within its subject area. The scale runs from 100 (highest rank) down to 1 (lowest rank).
  • If a journal has been assigned to more than one subject area, the CiteScore Percentile will be from the subject area in which the journal ranked the highest.
  • CiteScore uses approximately 22,000 journals plus conference papers and reviews indexed in the Scopus database as its source data.
  • The annual CiteScore covers articles published in the previous three years.
  • CiteScore includes front matter (editorials, news, letters to editors, etc.) in its calculations for how many documents are in each journal; consequently, journals with a lot of front matter, which is generally not cited, have a lower CiteScore (sometimes substantially lower) than their Journal Impact Factor (JIF).
  • CiteScore is produced by a major publisher (Elsevier) of journals which some have criticized as conflict of interest.

Other Sources of Journal Rankings

  • The h-index of a publication is the largest number h such that h articles published that publication have at least h citations each.
  • The h-core of a publication is a set of the h articles in a publication that the h-index is based on.
  • The h-median of a publication is the median number of citations for the articles that make up the h-core.
  • The h5-index, h5-core, and h5-median reflect the above counts for articles published in the last 5 complete calendar years.

The ASU Library acknowledges the twenty-three Native Nations that have inhabited this land for centuries. Arizona State University's four campuses are located in the Salt River Valley on ancestral territories of Indigenous peoples, including the Akimel O’odham (Pima) and Pee Posh (Maricopa) Indian Communities, whose care and keeping of these lands allows us to be here today. ASU Library acknowledges the sovereignty of these nations and seeks to foster an environment of success and possibility for Native American students and patrons. We are advocates for the incorporation of Indigenous knowledge systems and research methodologies within contemporary library practice. ASU Library welcomes members of the Akimel O’odham and Pee Posh, and all Native nations to the Library.