Alma Swan: The OA citation advantage: Studies and results to date

Philip Davis pmd8 at CORNELL.EDU
Thu Mar 11 12:17:50 EST 2010

In my critique of this review today (see: ), I 
commented on the inappropriate use of meta-analysis to the empirical OA 
citation studies:

"Meta-analysis is set of powerful statistical techniques for analyzing 
the literature. Its main function is to increase the statistical power 
of observation by combining separate empirical studies into one 
über-analysis. It’s assumed, however, that the studies are comparable 
(for instance, the same drug given to a random group of patients with 
multiple myeloma), but conducted at different times in different locales.

This is not the case with the empirical literature on open access and 
citations. Most of the studies to date are observational (simply 
observing the citation performance of two sets of articles), and most of 
these use no statistical controls to adjust for confounding variables. 
Some of the studies have focused on the effect of OA publishing, while 
others on OA self-archiving. To date, there is still only one published 
randomized controlled trial.

Conducting a meta-analysis on this disparate collection of studies is 
like taking a Veg-O-Matic to a seven-course dinner. Not only does it 
homogenize the context (and limitations) of each study into a brown and 
unseemly mess, but it assumes that homogenization of disparate studies 
somehow results in a clearer picture of scientific truth."

--Phil Davis

Stevan Harnad wrote:
>     ** Cross-Posted **
> [Note added by SH: These data are derived from Dr. Steve Hitchcock's
> bibliography of studies on the effect of open access and downloads
> ('hits') on citation impact. They are now ripe for a meta-analysis:
> You are encouraged to do one -- or to contact Dr. Swan and Dr.
> Hitchcock if you are interested in collaborating]
> ------------
> Swan, A. (2010) The Open Access citation advantage: Studies and
> results to date. Technical Report, School of Electronics & Computer
> Science, University of Southampton.
> This paper presents a summary of reported studies on the Open Access
> citation advantage. There is a brief introduction to the main issues
> involved in carrying out such studies, both methodological and
> interpretive. The study listing provides some details of the coverage,
> methodological approach and main conclusions of each study.

Philip M. Davis
PhD Student
Department of Communication
301 Kennedy Hall
Cornell University, Ithaca, NY 14853
email: pmd8 at
phone: 607 255-2124 

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