Discussion of relevance has permeated the information science literature for the past 50+ years, and yet we are no closer to resolution of the matter. In this research we developed a set of measures to operationalize the dimensions underpinning Saracevic's manifestations of relevance. We used an existing data set collected from 48 participants who used a web search engine to complete four search tasks that represent four subject domains. From this study which had assessed multiple aspects of the search process – from cognitive to behavioural – we derived a set of measures for cognitive, motivational, situational, topical and system relevances. Using regression analysis, we demonstrate how the measures partially predict search success, and additionally use factor analysis to identify the underlying constructs of relevance. The results show that Saracevic's five manifestations may be merged into three types that represent the user, system and the task.