Open Access = Obvious Success

Everybody "knows" that open access is better, it's just that the proof has been, er, thin on the ground. No more. This study in the (open access) PLoS Biology offers the first rigorous examination of open access and non-open access papers in the same journal (Proceedings of the National Academy of Sciences). The numbers indicate that open access is demonstrably better for the scientists that use it:

This comparison of the impact of OA and non-OA articles from the same journal in the first 4–16 mo after publication shows that OA articles are cited earlier and are, on average, cited more often than non-OA articles. To my knowledge, this is the first longitudinal study of a cohort of OA and non-OA articles providing direct and strong evidence for preferential or earlier citation of articles published originally as OA. It is also the first study showing an advantage of publishing an article as OA on the journal site over self-archiving (i.e., making the article otherwise online accessible).

Update: More positive news on the use of open access - caution: Microsoft Word format (via Open Access News).