When academic articles are "open access" or free online, they get read more often, but they don't -- going against conventional wisdom -- get cited more often in academic literature, finds a new Cornell study.

The reason, suggest Cornell graduate student Philip Davis and colleagues, including three Cornell professors, is that most researchers probably already have all the access they need to relevant articles.

"It appears that higher quality articles -- in other words, more citable articles -- are simply made freely available," said Davis. "Previous studies using different methods simply got cause and effect reversed." The study is published online in the British Medical Journal and will be published in the print edition Aug. 9.

The findings are particularly relevant to academic researchers, because the frequency with which a researcher's work is cited can be a factor in tenure and promotion decisions.

The researchers conducted the first controlled study of open-access publishing, randomly making some journal articles freely available while keeping others available by subscription only, to determine whether increased access to journal articles results in more article downloads and citations.

They found that in the year after the articles were published, open-access articles were downloaded more but were no more likely to be cited than subscription-based articles.

"The established dogma is that freely available scientific articles are cited more because they are read more," said Davis, a former science librarian who designed the study. "We found that open-access publishing may reach more readers than subscription-access publishing, but there is no evidence that freely accessible articles are cited any more than subscription-access articles."

The researchers randomly assigned 247 articles in 11 scientific journals, to free access. They measured how many times these articles were downloaded, the number of unique visitors to each article and how many times each article was cited.

"There were definitely more article downloads for freely accessible articles," said Davis. "Yet nearly half of these downloads were by Internet indexing robots like Google, crawling the Web for free content."

"There are many reasons to provide free access to the literature," said Davis. "A citation advantage, however, is not one of them."

Other co-authors are Bruce V. Lewenstein, professor of communication; Daniel H. Simon, assistant professor of economics; James G. Booth, professor of statistics; and Matthew J.L. Connolly, programmer and analyst, all at Cornell. The research was funded by the Andrew W. Mellon Foundation.