USF Shimberg Health Sciences Library

Write, Cite, Publish Library Guide


Bibliometrics is the statistical analysis of written publications, such as books or articles. In academic scholarship, bibliometrics are used to evaluate the influence that a particular author or publication has had upon a particular subject. These measurements are invaluable in determining which journals carry the most weight whether selecting source material or deciding where to submit your own work for publication. For more, see the tab on Impact Factors.

What is an Impact Factor?

Impact factor is a measure of the frequency with which the "average article" published in a given scholarly journal has been cited in a particular year or period and is often used to measure or describe the importance of a particular journal to its field. The Thomson-Reuters (formerly Institute for Scientific Information (ISI)) ranks, evaluates, and compares journals within subject categories and publishes the results in Journal Citation Reports. The new rankings come out in the Spring, for the previous year's journals.  Three years worth of data are required to calculate a Journal Impact Factor.

The formula to determine the 2008 impact factor for a journal would be calculated as follows:

A = the number of times articles published in the journal during 2006-7 were cited by other journals during 2008 
B = the number of articles or reviews that were published in the journal during 2006-7

2008 Impact factor for a journal = A/B

Impact Factor Controversy

Impact factors have a huge, but controversial, influence on the way published scientific research is perceived and evaluated. Numerous criticisms have been made of the system:

  1. Journal impact factors depend on the research field: high impact factors are likely in journals covering large areas of basic research and less likely in more subject-specific journals.
  2. Although Journal Citation Reports includes some non-English journals, the index is heavily skewed toward English-language journals, leaving out important international sources.
  3. Researchers may be more likely to pursue fashionable topics that have a higher likelihood of being published in a high-impact journal than to follow important avenues that may not be as popular.

Tools for Assessing a Journal's Importance (Impact):

The SCImago Journal & Country Rank is a portal that includes the journals and country scientific indicators developed from the information contained in the Scopus database. These indicators can be used to assess and analyze scientific domains.

This platform takes its name from the SCImago Journal Rank (SJR) indicator, developed by SCImago from the widely known algorithm Google PageRank™. This indicator shows the visibility of the journals contained in the Scopus database from 1996.

The h-index is an index to quantify an individual’s scientific research output.

-- J.E. Hirsch

The h-index is an index that attempts to measure both the productivity and citation impact of the published body of work of a scientist or scholar. The index is based on the set of the scientist's most cited papers and the number of citations that they have received in other publications. The h-index can be manually determined using citation databases or using automatic tools. 

The h-index shows how many papers published by the author have been cited proportionately. An index of h means that the author has h papers that have been cited at least h times. 

For example, if Dr. Jones has published eight papers but only five of them have been cited five or more times, the maximum h-index Dr. Jones can have is five. 

Publication with Number of Times Cited

  • Publication #1 - cited 33 times
  • Publication #2 - cited 27 times
  • Publication #3 - cited 11 times
  • Publication #4 - cited 8 times
  • Publication #5 - cited 7 times

  • Publication #6 - cited 3 times
  • Publication #7 - cited 2 times
  • Publication #8 - cited 0 times

Even though seven of the papers have received citations from other authors, Dr. Jones' h-index can be no higher than five. In order for his h-index to get to six, one of his other papers must have been cited at least six times.

Web of Science will calculate your h-index for you but all papers you wish to include must be in the Web of Science index. Other places to find the number of times a paper has been cited are in Scopus (not currently subscribed to by this institution) and Google Scholar. To find your h-index, list your publications sorted by the number of times each has been cited by others. Your h-index will be the last publication that has an equal or higher number of cites than the number of publications.

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