Assessing and Improving the Quality of SKOS Vocabularies

Controlled vocabularies are increasingly made available on the Web of Data using the Simple Knowledge Organization System (SKOS) ontology. Assessment of vocabulary quality is important for determining the suitability of vocabularies for reuse in applications and for improving vocabulary development processes. We define 26 quality issues, i.e., computable functions that expose potential quality problems. In an analysis of a representative set of 24SKOS vocabularies, we found all of them to contain structural errors and/or other quality problems. We propose a set of correction heuristics which we have used to automatically correct a significant proportion of the identified problems. Our reference implementations of these methods, the quality assessment tool qSKOS and the quality improvement tool Skosify, are available for reuse as open-source software.