When journal articles are made freely available from PubMed Central (PMC) — a government-run digital archive of biomedical articles — readership counts drop at journal websites, a new study reports. The decline in readership affects both full-text and the final PDF versions of the article and appears to be growing over time.
The article, “Public Accessibility of Biomedical Articles from PubMed Central Reduces Journal Readership“ was published online in The FASEB Journal on April 3, 2013.
In this study, I was able to expand upon a previous analysis of physiology articles to include over 13,000 articles published in 14 society-run biomedical journals in nutrition, experimental biology, physiology, and radiology.
The study compared the performance (as measured by full-text and PDF downloads) between articles deposited in PMC and made freely available 12 months after publication with articles that remained accessible from the journal site. All journals included in the study also provide free access to their articles 12 months after publication, so access status was not a factor in the study — I was comparing free journal access with free journal access plus free PMC access.
Controlling for differences in their performance within the first 12 months of publication, when all articles were accessible only by subscription, those articles made freely available from PMC after the 12-month embargo experienced a reduction of 21% full-text HTML downloads in their second year of publication. Estimates for the reduction in full text article downloads were as high as 26% for some journals.
And while the journals only deposited the full-text (XML) into the archive and not the final PDFs, free accessibility from PMC also reduced PDF downloads from the journal websites by 14%, on average.
Clearly, PMC is having an effect on journal-side traffic even when the publisher attempts to give their content away for free. The study also suggests that PMC’s “printer-friendly” PDF rendering of a full-text article may provide a viable substitute to the publisher’s PDF for many readers of the scientific literature.
If you use PubMed (the index, not the archive), you’ll notice that its search results give preferential visibility to the PMC copy over a link to the journal website even if the latter is available free to readers. Keeping readers within the PubMed literature domain appears to be a design strategy of the PubMed universe.
PMC is now the largest repository of free biomedical literature, populated, in large part, by articles deposited by publishers on behalf of their authors. It is not surprising that as PMC gets larger, its gravitational effect over the journals (moons) that populate it is only getting stronger. The effect of PMC on articles deposited in 2012 is much greater than articles deposited in 2009.
While PMC may be providing complementary access to readers traditionally underserved by scientific journals, the loss of article readership from the journal website may weaken the ability of the journal to build communities of interest around research papers, impede the communication of news and events to scientific society members and journal readers, and reduce the perceived value of the journal to institutional subscribers.
Some readers may argue that none of this matters for full open access journals, but I think they are missing the point of the study, which is about the organizing powers of journals, editors, and learned societies, and their abilities to build communities of discourse around scientific findings. If this were just about finding the most efficient mechanism to reproduce and distribute information, we already invented that decades ago. It’s called the Internet.