Failing to observe a significant OA citation Advantage within a year of publication (or a year and a half -- or longer, as the case may be) with randomized OA does not demonstrate that the many studies that do observe a significant OA citation Advantage with nonrandomized OA are simply reporting self-selection artifacts (i.e., selective provision of OA for the more highly citable articles)....
The many reports of the nonrandomized OA Citation Advantage are based on samples that were sufficiently large, and on a sufficiently long time-scale (almost never as short as a year) to detect a significant OA Citation Advantage.
A failure to observe a significant effect with small, early samples, on short time-scales -- whether randomized or nonrandomized -- is simple that: a failure to observe a significant effect: Keep testing till the size and duration of your sample of randomized and nonrandomized OA is big enough to test your self-selection hypothesis (i.e., comparable with the other studies that have detected the effect)....
Posted by
Peter Suber at 8/30/2008 11:51:00 AM.
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.
