A paper from James M. Donovan (U Kentucky) and Carol A. Watson (U Georgia) analyzes the pattern of citations in law journals and finds that legal scholars who publish in open access (free and freely copyable) journals are 50 percent more likely to be cited in subsequent papers than those who publish in traditional journals, which can be very expensive. It's easy to see why publishing your work in a forum that is easier to get hold of would lead to it being read and cited by your peers, and this has also been the pattern in scientific open access journals.
To date, there have been no studies focusing exclusively on the impact of open access on legal scholarship. We examine open access articles from three journals at the University of Georgia School of Law and confirm that legal scholarship freely available via open access improves an article's research impact. Open access legal scholarship - which today appears to account for almost half of the output of law faculties - can expect to receive 50% more citations than non-open access writings of similar age from the same venue.Citation Advantage of Open Access Legal Scholarship (Thanks, DaraMcQ, via Submitterator!)