Author Self-Citation in the General Medicine Literature

[Eugene Garfield]

Author Self-Citation in the General Medicine Literature

Author(s): Kulkarni, AV (Kulkarni, Abhaya V.); Aziz, B (Aziz, Brittany); Shams, I 
(Shams, Iffat); Busse, JW (Busse, Jason W.)
Source: PLOS ONE  Volume: 6  Issue: 6  Article Number: e20885  DOI: 
10.1371/journal.pone.0020885  Published: JUN 16 2011  

Abstract: Background: Author self-citation contributes to the overall citation 
count of an article and the impact factor of the journal in which it appears. 
Little is known, however, about the extent of self-citation in the general clinical 
medicine literature. The objective of this study was to determine the extent 
and temporal pattern of author self-citation and the article characteristics 
associated with author self-citation. 
Methodology/Principal Findings: We performed a retrospective cohort study of 
articles published in three high impact general medical journals (JAMA, Lancet, 
and New England Journal of Medicine) between October 1, 1999 and March 31, 
2000. We retrieved the number and percentage of author self-citations 
received by the article since publication, as of June 2008, from the Scopus 
citation database. Several article characteristics were extracted by two 
blinded, independent reviewers for each article in the cohort and analyzed in 
multivariable linear regression analyses. Since publication, author self-citations 
accounted for 6.5% (95% confidence interval 6.3-6.7%) of all citations 
received by the 328 articles in our sample. Self-citation peaked in 2002, 
declining annually thereafter. Studies with more authors, in cardiovascular 
medicine or infectious disease, and with smaller sample size were associated 
with more author self-citations and higher percentage of author self-citation 
(all p <= 0.01). 
Conclusions/Significance: Approximately 1 in 15 citations of articles in high-
profile general medicine journals are author self-citations. Self-citation peaks 
within about 2 years of publication and disproportionately affects impact 
factor. Studies most vulnerable to this effect are those with more authors, 
small sample size, and in cardiovascular medicine or infectious disease.

Language: English
Document Type: Article
KeyWords Plus: GOOGLE-SCHOLAR; JOURNALS; SCIENCE; SCOPUS; WEB

Addresses: [Kulkarni, AV; Aziz, B; Shams, I] Hosp Sick Children, Toronto, ON 
M5G 1X8, Canada
[Busse, JW] Inst Work & Hlth, Toronto, ON, Canada
[Busse, JW] McMaster Univ, Dept Clin Epidemiol & Biostat, Hamilton, ON, 
Canada
Reprint Address: Kulkarni, AV (reprint author), Hosp Sick Children, 555 Univ 
Ave, Toronto, ON M5G 1X8, Canada

E-mail Address: abhaya.kulkarni at sickkids.ca
ISSN: 1932-6203
Open Access: 
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.002088
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