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NR 700s: DNP: Journal Impact Factors

An impact factor is a quantitative measure of the importance of a journal, article, or researcher (author) relative to others in the same discipline, based on how frequently it is cited. There are several indexes that measure impact factors, but they do not use the same methodologies. This means they produce slightly different results. Therefore, you should use these data carefully. There are some controversial aspects of using impact factors:

  • It's not clear whether the number of times a paper is cited measures its actual quality. Sometimes research is cited as a bad example of something.
  • Some impact factor calculations include citations in textbooks, handbooks, and reference books, while others do not.
  • Some disciplines have many subject-specific journals, while others have very few. One should only compare journals and researchers within the same discipline.
  • Review articles are cited more often and can skew results.
  • Self-citing can skew results.

All of the information on this page is adapted from University of Washington Health Sciences Library guide on impact factors:

Impact Factor Resources

  • Eigenfactor score: overall value provided by all of the articles published in a journal in a year. 
  • Article Influence score: a measure of a journal's prestige based on per article citations and comparable to Impact Factor.
  • Eigenfactor measures journal price as well as citation influence. The Cost-Effectiveness Search orders journals by a measure of the value of the dollar they provide.
  • Ranks scholarly journals as well as newspapers, theses, popular magazines, etc.
  • Adjusts for citation differences across disciplines, allowing for better comparison across research area
  • SJR (SCImago Journal Rank): expresses the average number of weighted citations received in the selected year by the documents published in the selected journal in the three previous years.
  • Ranks journals and compares journal citation among countries.
  • Journals are assigned to major thematic categories as well as to specific subject categories.
  • Cited by # appears at the end of each item in the search result list. This link will display a list of articles and documents that have cited the document retrieved in the search. Note that this only includes resources indexed by Google Scholar.
  • Some criticisms of Google Scholar Cited References:
    • includes some non-scholarly citations
    • does not comprehensively or intentionally index specific resources, so it is unclear which resources are included
    • does not perform well for older publications
    • may find and count the same citing work more than once