Stevan Harnad and Tim Brody, Comparing the Impact of Open Access (OA) vs. Non-OA Articles in the Same Journals, D-Lib Magazine, June 2004. Excerpt: "The way to test the impact advantage of Open Access (OA) is not to compare the citation impact factors of OA and non-OA journals but to compare the citation counts of individual OA and non-OA articles appearing in the same (non-OA) journals. Such ongoing comparisons are revealing dramatic citation advantages for OA....The earlier Lawrence (2001) study on the impact-enhancing effects of OA in computer science needed to be replicated in other fields to check whether it was merely an artifact of the fact that computer science is conference-based rather than journal-based, and whether the advantage really reflected OA vs. non-OA rather than just online access vs. paper access. Fortunately, thanks to the ISI database licensed to the Observatoire des Sciences et des Technologies (OST) and a special contract generously provided by ISI to conduct the study, our research team at the Université du Québec à Montréal, Southampton University and Universität Oldenburg is in the process of testing the OA advantage across all disciplines in a 10-year ISI sample of 14 million articles. The physics analyses up to 2001 are already completed (Brody et al. 2004), and they reveal even larger effects than those reported by Lawrence, with OA/non-OA citation ratios of 2.5 - 5.8."
(PS: This is an important article. It's the first major study since the famous Lawrence paper documenting the proposition that OA increases impact. It's also the first to go beyond Lawrence in scope and method in order to answer doubts raised about his thesis. By confirming that OA increases impact, it gives authors the best of reasons to provide OA to their own work.)
Posted by
Peter Suber at 6/21/2004 09:43:00 PM.
The open access movement:
Putting peer-reviewed scientific and scholarly literature
on the internet. Making it available free of charge and
free of most copyright and licensing restrictions.
Removing the barriers to serious research.
I recommend the OA tracking project (OATP) as the best way to stay on top of new OA developments. You can read the OATP feed on a blog-like web page or subscribe to it by RSS, email, or Twitter. You can also help build the feed by tagging new developments you encounter.
