The most commonly cited author-level impact factor. The h-index was developed in 2005 by Jorge Hirsch, a physicist at the University of California in San Diego. Hirsch's paper was published in Proceedings of the National Academy of Science (PNAS).
In that paper he states: "A scientist has index h if h of his/her Np papers have at least h citations each, and the other (Np − h) papers have no more than h citations each."
The validity of the h-index, however, has been called into question.
Publish or Perish is a software program that retrieves and analyzes academic citations. It uses Google Scholar and Microsoft Academic Search to obtain the raw citations, then analyzes these and presents the following statistics:
It used to be that only the ISI Citation Indexes would list citing articles. That has changed, thanks to the linking abilities of the Web. Many databases will tell you that article X has been cited N times by articles in its database. Be aware that this number is based only on the articles indexed by that database; there may be other journals that cite your article that aren't listed in that database. So always check more than one database.
Below is a list of databases UK has subscriptions to that can serve as a starting place. Databases marked with an asterisk (*) have features to calculate h-index.
There is an international initiative that addresses problems arising from identifying researchers with similar or the same name. It is ORCID, which issues unique identifiers to distinguish individual researchers.
Each citation source produces slightly different results depending on the content and coverage of the source. This underscores the importance of using multiple citation sources to judge the true impact of an author's work. The search strategy should be broad and inclusive enough to accommodate the following pitfalls.
Properly identifying authors and their papers is difficult for obvious reasons. How many articles are authored by J. Smith, Y. Lee, or L. Jackson? The groups below are working to solve this problem.