Invisible institutional repositories: Addressing the low indexing ratios of IRs in Google Scholar

Google Scholar has difficulty indexing the contents of institutional repositories, and the authors hypothesize the reason is that most repositories use Dublin Core, which cannot express bibliographic citation information adequately for academic papers. Google Scholar makes specific recommendations for repositories, including the use of publishing industry metadata schemas over Dublin Core. This paper aims to test a theory that transforming metadata schemas in institutional repositories will lead to increased indexing by Google Scholar.

The authors conducted two surveys of institutional and disciplinary repositories across the USA, using different methodologies. They also conducted three pilot projects that transformed the metadata of a subset of papers from USpace, the University of Utah's institutional repository, and examined the results of Google Scholar's explicit harvests.

Repositories that use GS recommended metadata schemas and express them in HTML meta tags experienced significantly higher indexing ratios. The ease with which search engine crawlers can navigate a repository also seems to affect indexing ratio. The second and third metadata transformation pilot projects at Utah were successful, ultimately achieving an indexing ratio of greater than 90 percent.

The second survey is limited to 40 titles from each of seven repositories, for a total of 280 titles. A larger survey that covers more repositories may be useful.

Institutional repositories are achieving significant mass, and the rate of author citations from those repositories may affect university rankings. Lack of visibility in Google Scholar, however, will limit the ability of IRs to play a more significant role in those citation rates.

Transforming metadata can be a difficult and tedious process. The Institute of Museum and Library Services has recently awarded a National Leadership Grant to the University of Utah to continue SEO research with its partner, OCLC Inc., and to develop a toolkit that will include automated transformation mechanisms.

Little or no research has been published about improving the indexing ratio of institutional repositories in Google Scholar. The authors believe that they are the first to address the possibility of transforming IR metadata to improve indexing ratios in Google Scholar.