IRS13 Thesaurus, Phrase and Hierarchy Dictionaries chapter E. M. Keen Harvard University Gerard Salton Use, reproduction, or publication, in whole or in part, is permitted for any purpose of the United States Government. VII-36 Collection Average Rank of Relevant and Input Dictionary First Second Last Thesaurus-3 5.2 11.2 251.8 IRE-3 Phrases 4.6 10.4 235.2 Abstract Hierarchy - Parents 1.6 6.2 208.3 Hierarchy - All Relations 1.3 10.1 209.4 CRAN-l Thesaurus-3 4.5 9.7 66.2* Abstract Phrases 4.5 10.8 66.9 ADI Thesaurus-l 5.0 10.7 33.7 Text Phrases 5.7 9.9 33.9 * This result differs somewhat from that given in Fig. this comparison requires the use of output assigning different rank in cases of tied rank positions 14 because a slightly Comparison of Thesaurus with Phrases and Thesaurus with Hierarchy Using the Average Rank Positions of the First, Second and Last Ranked Relevant Documents. Fig. 25