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Randomized Controlled Trial
. 2008 Jul 31:337:a568.
doi: 10.1136/bmj.a568.

Open access publishing, article downloads, and citations: randomised controlled trial

Philip M Davis  1 , Bruce V Lewenstein, Daniel H Simon, James G Booth, Mathew J L Connolly
Affiliations
Randomized Controlled Trial

Open access publishing, article downloads, and citations: randomised controlled trial

Philip M Davis et al. BMJ. .

Abstract

Objective: To measure the effect of free access to the scientific literature on article downloads and citations.

Design: Randomised controlled trial.

Setting: 11 journals published by the American Physiological Society.

Participants: 1619 research articles and reviews.

Main outcome measures: Article readership (measured as downloads of full text, PDFs, and abstracts) and number of unique visitors (internet protocol addresses). Citations to articles were gathered from the Institute for Scientific Information after one year.

Interventions: Random assignment on online publication of articles published in 11 scientific journals to open access (treatment) or subscription access (control).

Results: Articles assigned to open access were associated with 89% more full text downloads (95% confidence interval 76% to 103%), 42% more PDF downloads (32% to 52%), and 23% more unique visitors (16% to 30%), but 24% fewer abstract downloads (-29% to -19%) than subscription access articles in the first six months after publication. Open access articles were no more likely to be cited than subscription access articles in the first year after publication. Fifty nine per cent of open access articles (146 of 247) were cited nine to 12 months after publication compared with 63% (859 of 1372) of subscription access articles. Logistic and negative binomial regression analysis of article citation counts confirmed no citation advantage for open access articles.

Conclusions: Open access publishing may reach more readers than subscription access publishing. No evidence was found of a citation advantage for open access articles in the first year after publication. The citation advantage from open access reported widely in the literature may be an artefact of other causes.

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Conflict of interest statement

Competing interests: None declared.

Figures

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Fig 1 Flow of study data
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Fig 2 Percentage differences (95% confidence intervals) in downloads of open access articles (n=247) and subscription access articles (n=1371) during the first six months after publication. Downloads from known internet robots are excluded
See this image and copyright information in PMC

Comment in

  • Open access to research.
    Godlee F. Godlee F. BMJ. 2008 Jul 31;337:a1051. doi: 10.1136/bmj.a1051. BMJ. 2008. PMID: 18669562 No abstract available.

References

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Publication types

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