(Phys.org) —A recent study paid for by the European Commission, and conducted and published by (the non-peer reviewed site) Science-Metrix, has found that more than half (approximately 55 percent) of peer-reviewed research articles that were originally published between the years 2007-2012 can now be accessed free of charge somewhere on the Internet—a marked increase over last year when papers from just one year reached that mark, Nature blog has reported. Researchers with the study also found that approximately 13 percent of peer-reviewed research papers were published directly to open access sites in 2012. Papers first published behind paywalls make their way to open access sites only after a certain time delay, usually, the researchers report, due to authors archiving their papers themselves.

The study was conducted as part of what is being called "open access" week, where proponents of open access use various methods to urge authors to go the open-access route. One such venture was the "Open Access Button" where users could press a button on a website to find open access papers on a topic of their choice. The idea, such proponents suggest, is to open a dialogue between authors and those who would like access to their papers without having to pay for them.

The research team used special software to scrape the Internet looking for published research papers as listed by the Scopus database for the period 1996-2013. Science-Metrix officials note that the numbers are of course estimates, as their software can't possibly find every instance of a paper. They believe the software misses approximately 5 to 6 percent of papers available.

Advocates of open access suggest the numbers found by the researchers don't mean much as the majority of articles originally published behind paywalls typically undergo a one to two year delay before being carried to open access sites—a lag that can prove important in fast changing fields.

The researchers also found that open access publication tended to vary by both region and subject area—Brazil and the Netherlands, for example both had very high rates of initial open access publication—76 and 74 percent respectively and biomedical papers were shared on average, freely, far more often than chemistry papers—71 and 39 percent respectively.

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