Review of Antelman's work on the OA impact advantage

Suzanne P. Lewis, Open Access Articles Have a Greater Research Impact Than Articles Not Freely Available, Evidence Based Library and Information Practice, 1, 3 (2006).  A review of Kristin Antelman, Do Open-Access Articles Have a Greater Research Impact? College & Research Libraries, 65, 5 (Sep. 2004) pp. 372-82.  From the abstract:

The four disciplines represented a range of open access uptake: 17% of articles in philosophy were open access, 29% in political science, 37% in electrical and electronic engineering, and 69% in mathematics. There was a significant difference in the mean citation rates for open access articles and non?open access articles in all four disciplines. The percentage difference in means was 45% in philosophy, 51% in electrical and electronic engineering, 86% in political science, and 91% in mathematics. Mathematics had the highest rate of open access availability of articles, but political science had the greatest difference in mean citation rates, suggesting there are other, discipline?specific factors apart from rate of open access uptake affecting research impact....

The finding that, across these four disciplines, open access articles have a greater research impact than non?open access articles, is only one aspect of the complex changes that are presently taking place in scholarly publishing and communication. However, it is useful information for librarians formulating strategies for building institutional repositories, or exploring open access publishing with patrons or publishers.