TOPICAL SUBJECT EXPERTISE AND THE SEMANTIC DISTANCE MODEL OF RELEVANCE ASSESSMENT

This paper reports two experiments that investigated the semantic dist ance model (SDM) of relevance assessment. In the first experiment grad uate students of mathematics and economics assessed the relevance rela tionships between bibliographic records and hierarchies of terms compo sed of classification headings or help-menu terms. The relevance asses sments of the classification headings, but not the help-menu terms, ex hibited both a semantic distance effect and a semantic direction effec t as predicted by the SDM. Topical subject expertise enhanced both the se effects. The second experiment investigated whether the poor perfor mance of the help-menu terms was an experimental design artifact refle cting the comparison of terse help terms with verbose classification h eadings. In the second experiment the help-menu terms were compared to a hierarchy of single-word terms where they exhibited both a semantic distance and semantic direction effect.