The more recent your version of DSpace is, the better. It is highly recommended to upgrade to DSpace 5.4 or newer, because of recent indexing related bugfixes.
Both the JSP and XML user interface expose DSpace metadata in a way that Google can pick it up for indexing.
The faster your site is, the better. If this indicator is above 1000 milliseconds you may need to optimize. Keep into account that this application is currently hosted in Belgium (Europe). As a result, the reported responsetime is affected by the geographical distance between your DSpace server and the server of this application.
The number of items in your repository is not necessarily a valuable metric for quality. However, it can be used as a ceiling value for assessing coverage in online indexes or harvesters.
It is possible that search engines are indexing much more pages than your items and bitstreams. While the indexing of collection and community pages is generally fine, you really don't want people to land on specific browse or discovery results pages. Comparing your item count with page hits from search engines is the first step in analysing this type of problem.
Following items have been analysed with this tool. Items in red were not found in Google Scholar. For the other ones, at the very minimum the metadata was confirmed as indexed in Google Scholar. The file icon is shown in green when the full text was found in scholar, and red if it wasn't.
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