Our declared objective is to promote the Open Access initiatives. One of the most promising ways to distribute the research output of the universities and research centers is to deposit scientific papers and related material at institutional or disciplinary repositories.

     The Ranking Web (Webometrics) provides a list of mainly research-oriented repositories arranged according a composite index derived from their web presence and the web impact (link visibility) of their contents, data obtained from the major commercial search engines. For being accepted in the Directory the following conditions are needed:

- Only repositories with an autonomous web domain or subdomain are included:

repository.xxx.zz (YES)

www.xxx.zz/repository (NO)

- The contents should be mainly scientific papers

     With the aim to improve visibility of repositories and good practices in their web publication we have extracted the following quantitative web indicators from the most important search engines. The methodology is similar, but not exactly the same, to those use in our other Rankings:

Size (S). Number of pages from Google
Visibility (V). The total number of external links received (backlinks) by the number of regerring domains for such links obtained from MajesticSEO databaser.
Rich Files (R). Files in formats like Adobe Acrobat (.pdf), MS Word (doc, docx), MS Powerpoint (ppt, pptx) and PostScript (.ps & .eps) extracted from Google.
Scholar (Sc). Using Google Scholar database we calculate the mean of the normalised total number of papers and those (recent papers) published between 2007 and 2011.

The four ranks were combined according to a formula where each one has a different weight but maintain the ratio 1:1 between activity (size sensu lato) and impact (visibility)

     Any remark regarding addition or deletion of academic repositories is welcomed, as well as any comments or suggestions that will help us to improve the Ranking.