IRS13 Scientific Report No. IRS-13 Information Storage and Retrieval Suffix 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. Stem Stem OM Suffix `S' Suffix `S' OM H' H' Precision Precision dh 1.0 - 1.0 0.8 0.6 -Q\ K 0.8 0.6 0.4 0.4 - 0.2 0.2 0 0.2 0.4 0.6 0.8 l.0[OCRerr] a) IRE-3, Abstracts, 3lf Requests I I I [OCRerr] Reca Recall 0 0.2 0.4 0.6 0.8 1.0 b) Cran-l, Abstracts, 1+2 Requests Performance Curves Comparing Stem and Suffix `S' Dictionaries on Two Collections Fig. 2.