ISR11 Scientific Report No. ISR-11 Information Storage and Retrieval Design Criteria for Automatic Information Systems chapter M. E. Lesk G. Salton Harvard University Gerard Salton Use, reproduction, or publication, in whole or in part, is permitted for any purpose of the United States Government. O[OCRerr]O Logical Stems (Null Logvec) X[OCRerr]X Weighted Stems [OCRerr]Full Null) PRECISION 0 x o\X[OCRerr]x[OCRerr]x 0.8 O\ \[OCRerr] 0.6 O[OCRerr]C x \o[OCRerr]o4x[OCRerr][OCRerr]\X 0.4 0.2 0 I g S I RECALL 0 0.2 0.4 0.6 0.8 1.0 Effectiveness of Weighted Word Stems (IRE-2 collection 17 requests) Fig. 6