Citation analysis - sometimes known as bibliometrics - is becoming increasingly important for research evaluation in the subject areas of Health and Science - areas which are mostly well covered by the citation indexes, Web of Science and Scopus.
Other subject areas
Citation analysis is not always appropriate in areas where research publications are not so well covered by the citation indexes. These include Arts & Humanities, most Social Sciences, (except some medically related areas), and to a lesser extent Maths, Engineering, Computer Science and Economics.
In these areas it is possible to derive citation information for online publications using Google Scholar
and other more specialised services (eg CiteSeer), and to calculate citation measures using free software tools (such as Publish or Perish), but this requires careful checking because Google Scholar relies on algorithms which do not always give accurate results.
Web of Science
can be used to calculate the h-index and other citation measures for an individual, but comparative analysis of groups and institutions requires specialised tools such as InCites
Jounal impact metrics
Some people use the Journal Impact Factors
of the journals in which researchers have published as a surrogate measure in research evaluation, but this is not to be recommended. The citation record for the individual is much more informative. Not every article in a high impact journal is well cited, and a highly cited article in a low/medium impact journal can have much higher significance. Using a tool like InCites provides infomation on actual article citation rates relative to the average citaiton rates for the journal.
The h-index was devised by the physicist Jorge Hirsch in 2005* who defined it as follows:
A scientist has index h if h of [their] Np papers have at least h citations each, and the other (Np - h) papers have at most h citations each.
Put another way, a scholar has an index of h if he has published at least h papers, each of which has been cited at least h times.
* Hirsch, J. E. (2005). "An index to quantify an individual's scientific research output". PNAS 102 (46): 16569–16572. doi:10.1073/pnas.0507655102.
For advice on citation analysis please contact your Information Specialist
or the Senior Information Specialist for Research Support.
Citations count! Making and Measuring your citation impact: