This week is Open Access Week, and this gives us the opportunity to highlight how RePEc has been promoting open access to economic literature since 1997 (and since 1992 with its predecessor projects). We want to distinguish here two ways research is open in economics: through pre-prints and through open access journals.
Pre-prints
Economics has a long tradition of pre-prints that predates the web. Usually called working papers or discussion papers, they have become popular because publication delays are very long in economics (measured in years). The origin of RePEc lies in making the dissemination of those pre-prints more efficient by providing central services for their discovery. Before, it was very difficult for those outside existing top institutions to know what the current frontier of research was. As is still valid now, publication in journals was really a historical record of where the research frontier was a few years earlier. Now, RePEc has records for over 800,000 pre-prints and disseminates them through web sites, mailing lists, RSS feeds and Twitter. They are also included in the citation analysis and they are indeed cited on a level field with journal articles. In fact, RePEc does not privilege journal articles over pre-prints, yet working papers are downloaded seven more times than the corresponding articles.
For those who stumble upon a journal article in a RePEc site, the alternative version as a pre-print is offered when available. This is particularly useful when the journal is gated: this allows the reader without a subscription to still have a read of the full paper. Sometimes it is not the final version, and sometimes it is even a more complete version as the editorial process may have required cuts. Such links from article to pre-print are particularly frequent for the most cited works.
Open access journals
RePEc is also indexing journal articles, and this includes the open access ones. Typically, they are noted with a special notice indicating that the full text can be downloaded freely. In addition, gated journals are not privileged in any way over open access ones: RePEc invites all journals to be indexed, as long as they are willing to follow our instructions. This allows small independent journals to get the same opportunity as journals from the largest commercial publishers to be searched and found on RePEc sites. In fact, free downloads does lead to more frequent downloads.
Posted by Christian Zimmermann 
The RePEc Blog 