Lansingh VC, Carter MJ "Does Open Access in Ophthalmology Affect How Articles Are Subsequently Cited in Research?" Opthalmology 116(8):1425-`431, August 2009

[Eugene Garfield]

E-mail Addresses: mearter at strategic-solutions.inc.com  

TITLE : Does Open Access in Ophthalmology Affect How Articles Are 
Subsequently Cited in Research?

Author(s): Lansingh VC (Lansingh, Van C.)2,3,4, Carter MJ (Carter, Marissa 
J.)1   

Source: OPHTHALMOLOGY    Volume: 116    Issue: 8    Pages: 1425-1431    

Published: AUG 2009    
Times Cited: 1     References: 14     Citation Map      

Abstract: 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. Ophthalmology 2009; 
116:1425-1431 (C) 2009 by the American Academy of Ophthalmology. 

Document Type: Article  
Language: English  
KeyWords Plus: JOURNAL IMPACT FACTOR; CITATION ADVANTAGE; ASSOCIATION 

Reprint Address: Carter, MJ (reprint author), Strateg Solut Inc, 1143 
Salsbury Ave, Cody, WY 82414 USA  
Addresses:  
1. Strateg Solut Inc, Cody, WY 82414 USA  
2. Fdn Vis, Asuncion, Paraguay  
3. Fdn Hugo Nano, Buenos Aires, DF Argentina  
4. IAPB, Buenos Aires, DF Argentina  

E-mail Addresses: mearter at strategic-solutions.inc.com  

Publisher: ELSEVIER SCIENCE INC, 360 PARK AVE SOUTH, NEW YORK, NY 10010-
1710 USA  

IDS Number: 480CT  
ISSN: 0161-6420  
DOI: 10.1016/j.ophtha.2008.12.052  

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