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Research Impacts Using Citation Metrics

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Julia Gelfand
Office: Science Library 228

Phone: 949-824-4971


Journal Impact Factor

An impact factor is a way of measuring the relative ranking of a journal within a particular field. Ranked lists of journals can be used to:

  • Identify prestigious and influential  journals in a particular discipline
  • Identify highly ranked journals in which to publish
  • Help determine the allocation of research funding

Journal Citation Reports (Web of Science coverage of 3 citation indexes)


ISI Journal Citation Reports offers a means to statistically compare and evaluate some of the world's leading journals. 

  • Delivers quantifiable statistical information based on citation data
  • Provides a variety of impact and influence metrics, including the Journal Impact Factor and Eigenfactor®
  • Includes rank-in-category tables, journal self-citations, and Impact Factor boxplots

JCR provides comparison data for how journals rank among other titles in a subject category and by citation value and impact factor.  One can also retrieve historical trend data for several years to see the direction of the impact.  However a specific article can trigger a measurement that is a one-time spike.

Using JCR

Go to ISI Journal Citation Reports.

You can see that it offers a choice of two collections - the JCR Science Edition (which includes medicine) and the JCR Social Sciences Edition, and that you will need to specify a year. Journals are included from 1999, and every August is updated with the previous year's data.

The database can be viewed by journal groupings (of subject, publication or country of origin); searched for a specific journal; or accessed in its entirety.

Searching the Science Edition, year 2011; and selecting to view journals by Subject Category, provides an opportunity to choose from a long list of categories. Selecting "Computer Science - Artificial Intelligence" and clicking on Submit provides 111 results, sorted alphabetically by journal title.

JCR CS results

The list can be resorted by the following options.

Sorting by Impact Factor, for example, can give a better idea of the most important journals in the field.

Clicking on a journal's name gives more specific information about that journal, including the option to view various graphs.

Click on the Impact Factor Trend Graph.

Information such as this can help you see how a journal's impact factor has changed over time. Comparisons with other journals might indicate rising or decreasing influence. However, due to differences in databases and algorithms, more than one type of ranking index should be consulted in the overall analysis of a journal's significance in a field. (Note that Eigenfactor Scores can also be viewed here.)

By studying journal impact metrics, such as those presented in this database, scholarly researchers and academic organizations can make better informed decisions about the importance of the journals they purchase and publish in.




Other Journal Ranking Systems

The Excellence in Research for Australia (ERA) Initiative  assesses research quality within Australia's higher education institutions using a combination of indicators and expert review by committees comprising experienced, internationally-recognized experts.

ABDC Journal Ratings List  is a journal quality list published by the Australian Business Deans Council in 2008 and revised in 2010. It ranks journals in 15 sub-disciplines in business, economics and law.

European Reference Index for the Humanities initial lists  is a list of journals ranked by expert panels in 15 sub-disciplines in the humanities. Disciplines include Art, Architectural and Design History, Linguistics, Pedagogical and Educational research and Psychology.

Source Normalized Impact per Paper (SNIP)

SNIP is one of the calculators in Scopus and requires login and registration.  SNIP 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.”  Additional explanations and information is available at  CWTS Journal Indicators.

CiteScore powered by Scopus

CiteScore was launched in December 2016 by Elsevier and is part of it's Scopus database (found under the Sources tab).  It provides the average citations per document that a title receives over 3 years. The data includes SNIP (Source Normalized Impact per Paper), SJR (SCImago Journal Rank), citation- and document- counts and percentage cited. The integration of these metrics into Scopus provides insights into the citation impact of more than 38,000 titles, including >22,000 journals and >15,000 conference proceedings, book series, and trade journals all indexed by Scopus from 2014.  There are 8 complimentary indicators that perform individually and cover the following elements: 

  • CiteScore
  • CiteScore Tracker
  • CiteScore Percentile
  • CiteScore Quartiles
  • CiteScore Rank
  • Citation Count
  • Document Count
  • Percentage Cited

Calculated annually, it reflects a 3 year window and includes all content within the publication or document that gives a bigger picture of publication impact than just the cited article.  For a current snapshot, monthly views of how a journal performs is noted as impact can change during the course of a year's data. 

SCImago Journal Rank (powered by Scopus)

SCImago (SJR) uses Scopus journal information to allow users to search and analyze journal and country rankings. It is "based on the transfer of prestige from a journal to another one; such prestige is tranfered through the references that a journal do to the rest of the journals and to itself."

The global comparisons show citable documents, citations, self-citations, citations, per document and the H-index and can be downloaded by country.  Visualization tools are also included to explain different ways to map or chart publication data.

InCites from Web of Science

Hosted by Clarivate, and part of the Web of Science portfolio, InCites requires a special subscription and registration.  UCI is a subscriber.  InCites demonstrates that it is a citation-based evaluation tool that compares and analyzes people, programs and peers and is useful for academic and government administrators to analyze institutional productivity and benchmark output against peers and aspirational peers in a national worldwide. Allows for quick reports to be generated and shared.  You can also use InCites to see individuals' research output.



Google Scholar Metrics

Google Scholar

Google Scholar Metrics

Google Scholar Metrics uses the H-Index formula to rank journals. The Metrics Home Page lists the top 100 h5-index ranked publications in English.

"The h5-index is the h-index for articles published in the last 5 complete years. It is the largest number h such that h articles published in 2007-2011 have at least h citations."

Because disciplines have varying publishing models and expectations, comparing journal citation indices across research areas is not recommended. However, Google Scholar Metrics also provides 5h-index ranked lists by subject area. Researchers can select language, discipline category, and, if desired, a subject sub-category. (E.g. category: Chemical & Material Sciences; subcategory: Ceramic Engineering.) There are many subcategories to choose from.

Google Scholar Metrics categories:


By clicking on the h5-index for each journal, one can access the references for the most cited articles and the number of times each article was cited within that 5-year period.

Clicking on the Cited by number within each reference provides a list of those articles.

Clicking on an article name can lead to a source and sometimes full text. (To gain free access to an article, one may need to log into UCI databases. Library Search can be searched by journal name to find the appropriate database.)

Warning: Google Scholar Metrics is limited to articles indexed in Google Scholar, a database that does not have set journal inclusion parameters. For best results, multiple sources and methods should be used in identifying the most significant journals and articles in a research area.




The Eigenfactor™ Score uses a network of citation data to assess the relative importance of journals in the science and social science communities. Journals with many citations from influential journals are rated as influential themselves.

The Article Influence™ Score determines the average influence of a journal's articles.

Score calculation is based on the citations received over a five year period, but it also considers which journals have contributed these citations so that highly cited journals will influence the network more than lesser cited journals. References from one article in a journal to another article from the same journal are removed, so that Eigenfactor Scores are not influenced by journal self-citation.

Since the number and frequency of citations vary by discipline, the Eigenfactor algorithm adjusts for these differences.

In addition to articles from scholarly journals, Eigenfactor also includes newspaper articles, theses, popular magazines and other items in its reference material.

Eigenfactor scores can also be viewed within ISI Journal Citation Reports.