IRS13 Test Environment 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. i-lb Stages Input Content Analysis Variables Document Length Text Abstracts Titles Indexing Dictionaries Suffix `5' Stem Thesaurus Hierarchy Phrases Syntax Concon Section V V V V VI VI VII VII VII Ix Numeric Vectors Logical Vectors Matching Functions Cosine Correlation Search Overlap Correlation Other Correlations weighted Concepts III III III III IV The Input, Analysis and Search Variables Tested, including the Section Number in the present Report Fig. 6