Measuring Research Impact: Author Metrics

URL: https://libguides.cmich.edu/researchimpact

Citation Count

Citation count -- the total number of times an author's work has been cited

Keep in mind: Citation analysis as a qualitative measurement should be used cautiously, for the following reasons:

  • Citation rates and practices vary widely between disciplines.  Citation analysis of scholars in one field should not be compared to those in another.
  • Where a scholar publishes can have a great impact on the analysis if the tools used to count citations do not index the publications where a scholarly work is cited. This is particularly true for those that publish in international journals, smaller regional or local publications, or in non-journal sources such as books.
  • Citation rates can be influenced by practices such as self-citation.

H-index

H-index (or Hirsch index), is the most used author metric. It was created by the physician Jorge E. Hirsch in 2005 (California University).

It is based on the number of publications and the number of citations.

Keep in mind:

Before consulting your h-indexes, do not forget that different databases will give different h-indexes because of the coverage (years, kind and quantity of sources) of each database:

  • by Microsoft Research
    • Create a profile to consult your h-index or g-index
    • Coverage (scholarly publications discovered and indexed by Bing)
    • Updated: unknown
  • Publish or Perish (Free downloadable software for academic citations analysis)
    • Coverage (Google Scholar, Microsoft Academic Search, etc.)
    • Provider of h-index, g-index, total number of publications and citations and average citation per publication
  • Web of Science
    • Coverage (from 1900 - present for some journals): less content than Scopus in the social sciences
    • Search by author name or researcher identifier (ORCID or ResearchID) and click on “create citation report” in the upper right corner
    • Citation report includes: h-index, visual presentation of publications per year and citations per year, total times cited, average times cited
    • Updated: weekly

The H-index corresponds to the number of articles (N) on a list of publications ranked in descending order by the times cited that have N or more citations.

If somebody has an h-index of 5, it means that 5 of his articles have been cited at least 5 times each.


Articles Citations
1 46
2 25
3 12
4 11
5 5 = H-Index
6 4
7 2
8 1

 

 

 

 

 

 

 

 

 

Wikimedia Commons http://en.wikipedia.org/wiki/File:H-index-en.svg

Keep in mind:

  • The same author h-index may vary from one database to another, depending on the coverage of each database
  • Co-publishing can elevate the h-index, because it does not take the order of authorship into account
  • Time helps to increase the h-index; young researchers generally have a low h-index
  • The subject area can affect the H-Index: a researcher who publishes on a trendy subject will have a higher h-index than another one who publishes on a niche topic
  • The language of the publication affects the h-index; publications written in English receive more citations
  • Open access publishing increases the visibility of articles and their chance to be cited
  • Promotion of publications (blog posts, academic social networking, preliminary research findings at conferences,...) helps to make articles more visible and increases their chance of being cited
  • H-index takes self-citations into account; some high h-indexes are due to self-citation abuses

Publish or Perish (PoP) - A DIY Approach

Calculate your own h-index and other author indexes - It is a free software program that can be download onto a computer. It designed to help researchers manipulate Google Scholar citations to create their databases of citations from which they can generate their own metrics.  

Alternatives: g-index, i10-index

"G-index is introduced as an improvement of the h-index of Hirsch to measure the global citation performance of a set of articles. If this set is ranked in decreasing order of the number of citations that they received, the g-index is the (unique) largest number such that the top g articles received (together) at least g2 citations" (Egghe, L., “Theory and practice of the G-index”. Scientometrics, vol. 69, no. 1, (2006), pp. 131–152).

Keep in mind:

  • The g-index gives more weight to highly-cited articles (whereas the h-index is insensitive to it)
  • Someone's g-index will always be equal to or greater than the h-index

The i10-index was created by Google Scholar (Google Scholar Blog, 2011):

i10-Index = the number of publications with at least 10 citations

Keep in mind:

  • It is only accessible from Google Scholar Citations (author profile) (you need a Google account to manage your profile)
  • The i10-index is easy to calculate

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