It has been shown that by abstracting from tool-specific representations of linguistic annotations, annotations from different tagsets can be represented with reference to the OLiA ontologies (and/or with other OWL/RDF-based terminology repositories linked as External Reference Models).
it is possible to compare an existing reference annotation with annotations produced by NLP tools that use independently developed and differently structured annotation schemes (such as Connexor vs. RFTagger vs. Morphisto).