Relevance Auras: Macro Patterns and Micro Scatter

Abstract

Empirical analysis of relevance assessments can illuminate how different groups of readers perceive the relationship between bibliographic records and index terms. This experiment harvested relevance assessments from two groups: engineering students (here after "engineers") and library school students ("librarians"). These groups assessed the relevance relationships between bibliographic records and index terms for three literatures: engineering, psychology and education. Assessment included the indexer-selected term (the topically relevant term) as well as broader, narrower and related terms. Figures 1 - 8 show these terms arranged as twodimensional term domains. Positive relevance assessments plotted across the twodimensional term domains revealed regular patterns, here called "relevance auras." A relevance aura is a penumbra ofpositive relevance, emanating from a bibliographic records across a term domain ofbroader, narrower and related index terms. This experiment attempted to compare the relevance auras produced by engineers and librarians at both a macro and micro level of aggregation.