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Mathematics & Statistics: Subject Guide: Write/Cite/Publish

Citation Tools

EndNote is a paid citation manager, but it is available for free to GSU students, faculty, and staff from the GSU software downloads page. For help, check out the GSU EndNote Libguide.

Zotero is a free citation management tool supported by GSU Library faculty. For help, check out the GSU Zotero Libguide.

Mendeley is a free citation management tool that also incorporates social networking features for researchers. For help, check out the GSU Mendeley LibGuide.

Journal Impact Factors

 Journal Rankings & Impact Factors

Impact factor is a measure of the relative importance of a journal. Impact factors give a quantitative measure of a journal’s influence and impact compared to other journals. 

For a 2008 journal, the Impact Factor (IF) = A/B

A = the number of times articles published in 2006-7 were cited in indexed journals during 2008 
B = the number of articles, reviews, proceedings or notes published in 2006-7 

So, a 2008 journal with an Impact Factor (IF) of 3.333 means that on average, each of its 2006 and 2007 articles was cited 3.333 times in 2008.

1. Journal Citation Reports (JCR)

  •  Subscription.  Searches by journal or category or a customized search. Other data is also available (e.g., five-year impact factor, Immediacy Index, Cited-half Life, rank in category, etc.,).


  • Free. Uses all ISI data in an algorithm like Google’s PageRank. Looks at 5 years of data, removes self-citations, and is available in JCR.
  • Gives the Article Influence score (i.e., average influence per article of the papers in a journal, which is similar to impact factor).  Also gives the Eigenfactor score (i.e., a measure of the total importance (or value) to science). These scores are scaled down such that all journals listed in JCR are 100. The cost effectiveness values are also provided.

3. Scimago Journal Rank  

  • Free. Similar to eigenfactor, but based on citations in Scopus. Uses PageRank algorithm with 3 years of citation data and no self-citations. Contains >1300 journals, which are more internationally diverse 

4. Publish or Perish (PoP)  

  • Free. Based on Google Scholar citations. Analyzes 999 or fewer entries by author and journal. Gives average cites/paper, average number authors/paper, and h-index.

5. In-Cites

  • A website from Thompson's Essential Science Indicators. Includes citation count information, impact statistics, and assessments of scholarly achievement by author, institution, country, and journal.  The "Sci-Bytes" section contains "Hot Papers" and top impact rankings by subject field.

6. Others

Journal Usage Factors (Journal Usage Data)

Y Factor (IF & Weighted PageRank from Google)

MESUR (Metrics from Scholarly Usage of Resources) by RedJasper

Criticisms of impact factors

  • Includes a limited subset of journals (only uses articles cited by about 9000 journals)
  • Some disciplines are not completely covered
  • Biased towards English–language journals
  • The number is an average that includes self-citations
  • Only citable articles are included in the IF equation 
  • Editors can skew data by increasing the number of review articles (adding more citations) or increasing number of news items


1. PLoS Medicine Editors (June 6, 2006). "The Impact Factor Game". PLoS Medicine. doi:10.1371/journal.pmed.0030291.

2. Joint Committee on Quantitative Assessment of Research (June 12, 2008). "Citation Statistics" (PDF). International Mathematical Union.  Joint Committee on Quantitative Assessment of Research (June 12, 2008). "Citation Statistics" (PDF). International Mathematical Union. 

3. Seglen PO (1997). "Why the impact factor of journals should not be used for evaluating research". BMJ 314 (7079): 498–502. PMID 9056804. PMC: 2126010

4. C. T. Bergstrom. (May 2007). "Eigenfactor: Measuring the value and prestige of scholarly journals". College & Research Libraries News 68 (5).

5. Johan Bollen, Marko A. Rodriguez, and Herbert Van de Sompel. (December 2006). "Journal Status". Scientometrics 69 (3). 

Author Impact Factors

Author Impact Factor: h-Index

The h-index assesses scientific productivity of a scientist, group, or institution via quantity (# papers) and quality (# citations). In other words, the index is based on a balance between the scientist's most-cited papers and the number of citations per publication.
An h-Index of 25 means that the author has 25 publications that have received at least 25 citations.

An h-index can be obtained from:

1. Web of Science database, using the "Create Citation Report" icon

2. Scopus

Writing Styles