Understanding Impact Factors

What Is an Impact Factor?

Demonstrating a quantifiable measure of your publication output is a vital requirement from funding bodies. Establishing your status through publication in high-impact journals may also be important in establishing your status in your field. This measure is defined as an impact factor.

A journal impact factor is based on how often articles published in that journal during the previous two years (eg. 2007 & 2008) were cited by articles published in the most recent year for which JCR data is available i.e. 2009. Therefore a journal with high impact factor indicates that the articles in that journal have been cited frequently by other articles. This can be an indication of how prestigious a journal is in its field.

Interpreting Citation Analysis Data

When interpreting citation analysis data there are a number of important influencing factors to consider:

  • Field or discipline variation: Not all journals have impact factors, and the importance of impact factors will vary between disciplines
  • New Journals will have a low impact factor
  • Review articles: Authors and journals that frequently publish review articles tend to have their citation counts and impact exaggerated because these types of articles are usually highly cited
  • Longevity: The two-year “citation window” in the impact factor formula fails to capture the “long term value” or the real impact of many journals
  • Negative citations: The index ignores why an item was cited in the first place. So negative citations to incorrect work are counted

What Is a Journal’s Impact Factor?

The journal Impact Factor is the average number of times articles from the journal published in the past two years have been cited in the Journal Citation Reports (JCR) year.

The Impact Factor is calculated by dividing the number of citations in the JCR year by the total number of articles published in the two previous years. An Impact Factor of 1.0 means that, on average, the articles published one or two years ago have been cited one time. An Impact Factor of 2.5 means that, on average, the articles published one or two years ago have been cited two and a half times. Citing articles may be from the same journal; most citing articles are from different journals.

The journal Impact Factor was developed by Eugene Garfield at the Institute for Scientific Information (ISI), now owned by Thomson Reuters.

Impact Factor uses Thomson Reuters (ISI Web of Knowledge) citation data.

How to Find Impact Factor?

Use the Journal Citation Reports (JCR) to locate impact factors. The JCR also lists journals and their impact factors and ranking in the context of their specific field(s).

Step by Step:

  1. On the Library's Home page under Research Help, click on the Web of Science link
  2. Click on Journal Citation Reports at the top of the Web of Science page or under Additional Resources
  3. Journals are listed by Journal by Rank (ranking of each journal title) or Journal by Category (subject areas)
  4. Type in the journal title (or part of the title) in the search box under journal profile and click search button
  5. You will be taken to the Master search - listing all titles with similar names. Click on the title you need
  6. The Journal details can be seen along with key indicators table for with IF for each year IF for 5years and othe statistics
  7. Journal by category - to view journals by the subject categories (there are 232) . Each category gives the total IF , median IF , aggregate IF and other statistics
  8. Searches can be refined by choosing the subject, year range of years, publisher , region and JIF quartile

JCR and Impact Factor

Journal Citation Reports — JCR provides Impact Factors for all the journals indexed by Web of Science. Impact Factor allows for the comparison and ranking of journals within the same discipline. The Impact Factor only measures the interest of other researchers in an article, not its importance and usefulness. More information on impact Factor: with JCR training videos and How to use JCR wisely.

Other Measures Included in JCR

In addition to the impact factor, Journal Citation Reports lists other measures for included journals.

  • 5-Year Impact Factor
  • Immediancy Index
  • Cited Half-Life
  • Eigenfactor Score
  • Article Influence Score

To read more click here.

Factors That Influence Impact Factor

  • Date of Publication
  • Large vs. Small Journals
  • Average Citation
  • Review Articles
  • Changing / Growing Fields
  • ISI's Indexing / Citation Focus
  • Research vs. Clinical Journals

For more details read here:

Journal Quality List — The Journal Quality List is a collation of journal rankings from a variety of sources.

Journal Ranking — Journal-ranking.com allows users to configure their ranking interests, as well as provide a more reasonable method to evaluate a journal’s impact.

Journal Impact Factor — A Journal Impact Factor is a multidisciplinary tool for ranking, evaluating, and comparing journals within subject categories.

Databases for Scholars

Access valuable databases to enhance your scholarly endeavors. Cabells Scholarly Analytics aids in making informed publishing decisions by offering information about journals' submission guidelines, peer review policies, fees, and metrics for over 11,000 global academic publications.

To delve deeper into these resources, explore the details provided below on this page.

Examples of Journals With the Highest Impact Factors

An Example of Journals With High Impact Factors in the Subject: Business and Finance

Cabells Scholarly Analytics

Make the best publishing decision by using Cabells to avoid deceptive practices and select the best journal for your needs. View the submission info, peer review policies, and fees, for over 11,000 top global academic publications. Includes metrics.


Access abstracts and indexed bibliometric data for thousands of journal titles and millions of author profiles. Use sophisticated alt-metric tools to track the impact of your research.

Web of Science

Access abstracts and indexed bibliometric data for thousands of journals and millions of author profiles. Use altmetric analytical tools to track the impact of your research.