CRANV1P1 ASLIB Cranfield Research Project: Factors Determining the Performance of Indexing Systems: VOLUME 1. Design, Part 1. Text Formation of Index Languages chapter Cyril Cleverdon Jack Mills Michael Keen Cranfield An investigation supported by a grant to Aslib by the National Science Foundation. Use, reproduction, or publication, in whole or in part, is permitted for any purpose of the United States Government. - 60 - 100 9O 80 70 60 50 40 30 20 lO 0 0 [OCRerr]- = ASTIR (7030 Terms) .... AEC (12704 Terms) I I | I I 1 I I I 10 20 30 40 50 60 70 80 90 % of Index Terms (Ranked by Usage) 100 FIGURE 5.2 PATTERNS OF TERM USAGE (original (Original figure taken from 'Centralisation and Documentation", Arthur D. Little Inc)