“…When E = 0, P = R = 1.0, and when E = 1, P = R = 0.0. The E measure has been selected because it provides the opportunity to compare results of the current investigation with existing clusterbased retrieval results (Croft, 1980;Van Rijsbergen, 1974a;Van Rijsbergen & Croft, 197.5;Willett, 1984), especially the comprehensive results provided by Griffiths, Luckhurst, & Willett (1986).…”