<DOC> 
<DOCNO> IRS13 </DOCNO>         
<TITLE> Scientific Report No. IRS-13 Information Storage and Retrieval </TITLE>         
<SUBTITLE> Word-Word Associations in Document Retrieval Systems </SUBTITLE>         
<TYPE> chapter </TYPE>         
<PAGE CHAPTER="9" NUMBER="33">                   
<AUTHOR1> M. E. Lesk </AUTHOR1>  
<PUBLISHER> Harvard University </PUBLISHER> 
<EDITOR1> Gerard Salton </EDITOR1> 
<COPYRIGHT MTH="December" DAY="" YEAR="1967" BY="National Science Foundation">   
Use, reproduction, or publication, in whole or in part, is permitted for any purpose of the United States Government. 
</COPYRIGHT> 
<BODY> 
                                                            IX-33


      Cutoff    Rank Recall   Log Precision


        .30        .3247          .4770

        .45        .3409          .4982

        .60        .3162          .4888

        .75        .3116          .4932

        .90        .2933          .4608


All runs cosine correlation, frequency range 6-50


             Effect of Varying Cutoff


                     Table 10

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</DOC>