Thesauri or Ontologies ? Or both ? A Comparison between Two Kinds of Subject Heading Systems with Regard to their Enhancement of Effective Information Retrieval Taeda

We compare thesauri and ontologies, with regard to their enhancement of effective informationretrieval (the IR-effectiveness, specified as a balance between the moderate level of recall and precision). Subject heading systems should conform to the following PSSSI-properties, so as to enhance the IR-effectiveness: predictability, scalability, simplicity, serendipity and interoperability. We have carried out a theoretical study (grounded in logical analysis) and an empirical study (based on structured interviews) so as to see how the Library of Congress Subject Headings (LCSH)/Svenska ämnesord (SAO) thesauri, and the Language and Logic Links Ontology (LoLaLi) comply with the PSSSI-properties. LCSH enhances recall; it would profit from better scalability, administrative simplicity and certain aspects of serendipity and interoperability. SAO improves recall; it might be better in scalability, simplicity, serendipity and interoperability. LoLaLi enhances both recall and precision; it may be better in information-seeking simplicity and interoperability. Ämnesord Informationsåtervinning, Library of Congress Subject Headings, Logic and Language Links ontologi (LoLaLi), ontologier, tesaurer, ämnesord