Qualitative Investigation of the Disappearance of Classes and Individuals with Newer Versions of Terminologie

Terminology terms can be used to annotate data in a machine-readable and -understandable way, e.g. keywords describing datasets or publications can be annotated with the URLs of the corresponding terms in a vocabulary or ontology. Unfortunately, this annotation becomes useless if the corresponding URLs are no longer resolvable. This can happen e.g. if a new version of a terminology does not contain a specific term any more and if this term has not been marked as deprecated, but has been deleted. We therefore wondered whether this had happened before in the terminologies we have collected in the Earth System Science (ESS) collection of the TIB Terminology Service.

We investigated the persistence of classes and individuals of 32 terminologies in the ESS collection. We aimed for a qualitative rather than a quantitative analysis, i.e. we only examined successive earlier versions of a given terminology until we found deleted classes or individuals. Where appropriate, we either compared different versions of a term or analysed the timeline, tracking changes. In six of the 32 terminologies, we found classes or individuals that had been deleted. Additional checks revealed that the corresponding URLs were no longer resolvable. As we did not automatically check whether URLs of all terms of the terminologies were still resolvable, there may be additional classes and individuals with broken links in the analysed terminologies.