July 2009 Edition!

The number of repositories is growing fast worldwide but still many of them does not have their own domain or subdomain, and for this reason it is not possible to add them in our analysis. Some institutions maintain several databases with completely different URLs which penalize the global visibility they have. We are still unable to add usage/download statics but there are many initiatives already working on standardization of the collecting methods, so we expect that global data could be available soon.

Following several requests we now show two global Rankings. One that covers all repositories as was shown in previous editions (Top 400), and a new one that focus only on Institutional Repositories (Top 400 Institutional).

The major change introduced in this edition relates to the way the composite index (World Ranking) is computed, as we are now combining normalized values instead of ranks. The visibility is calculated giving extra importance to the external inlinks not coming from generic domains (.com, .org, .net). As in the last edition, the figures for rich files (pdf, doc, ppt, ps) are combined and not treated individually.

Comments on results

The composition of some repositories is so diverse that we decided to exclude those with only very large bibliographic databases (Dialnet, DTIC). CiteSeer is also excluded because is almost already replaced by the new version CiteSeerX. The French HAL central repository is excluded only from the institutional list in which it still appears their subsets like INRIA, Social Sciences and Humanities (HAL-SHS) or IN2P3. Finally, DiVa provides individual subdomains for each university, so this metarepository disappears from the main list.

Important repositories like PubMedCentral, CiteSeerX and Smithsonian/NASA Astrophysics Data System, do not use standard suffixes to design their contents (e.g. papers in acrobat format with file names which extension is not .pdf). This is a bad practice as it reduces the visibility of these documents to the search engines.

As usual we will thank your comments if you address them to our MAILBOX.