Does Open Access in Ophthalmology Affect How Articles Are Subsequently Cited in Research?
Received 17 October 2008; received in revised form 1 December 2008; accepted 19 December 2009. published online 22 June 2009.
Objective
To determine whether the concept of open access affects how articles are cited in the field of ophthalmology.
Design
Type of meta-analysis.
Participants
Examination of 480 articles in ophthalmology in the experimental protocol and 415 articles in the control protocol.
Methods
Four subject areas were chosen to search the ophthalmology literature in the PubMed database using the terms “cataract,” “diabetic retinopathy,” “glaucoma,” and “refractive errors.” Searching started in December of 2003 and worked back in time to the beginning of the year. The number of subsequent citations for equal numbers of both open access and closed access (by subscription) articles was quantified using the Scopus database and Google search engine. Number of authors, article type, country/region in which the article was published, language, and funding data were also collected for each article. A control protocol was also carried out to ascertain that the sampling method was not systematically biased by matching 6 ophthalmology journals (3 open access, 3 closed access) using their impact factors, and employing the same search methodology to sample open access and closed access articles.
Main Outcome Measures
Number of citations.
Results
The total number of citations was significantly higher for open access articles compared to closed access articles for Scopus (mean 15.2 versus 11.5, P < .0005, Mann-Whitney U = 20029, and Google (mean 6.4 versus 4.0, P < .0005, Mann-Whitney U = 21281). However, univariate general linear model (GLM) analysis showed that access was not a significant factor that explained the citation data. Author number, country/region of publication, subject area, language, and funding were the variables that had the most effect and were statistically significant. Control protocol results showed no significant difference between open and closed access articles in regard to number of citations found by Scopus: open access: mean = 17.8; SD (standard deviation) = 23.70; closed access: mean = 19.1; SD = 20.31; Mann-Whitney test, P = 0.730, Mann-Whitney U = 20584.
Conclusions
Unlike other fields of science, open access thus far has not affected how ophthalmology articles are cited in the literature.
Financial Disclosure(s)
The authors have no proprietary or commercial interest in any materials discussed in this article.
Financial Disclosure(s): The authors have no proprietary or commercial interest in any materials discussed in this article.
VCL reports being employed by a commercial entity (IAPB). MJC reports being employed by a commercial entity (Strategic Solutions, Inc.) and is a paid consultant to both Fundacion Vision and the IAPB.
ABSTRACT