MONO91 Table of Contents table of contents Mary Elizabeth Stevens National Bureau of Standards Page 5. Automatic classification and categorization 106 5.1 Factor analysis 108 5.2 The theory of clumps 110 5.3 Latent class analysis 113 5.4 Examples of other proposed classificatory techniques 113 6. Other potentially related research 114 6.1 Thesaurus construction, use and up-dating 114 6.2 Statistical association techniques 118 6.2.1 Devices to display associations: EDIAC 119 6.2.2 Statistical association factors - Stiles 119 6.2.3 The association map - Doyle and related work at SDC 122 6.2.4 Work of Giuliano and associates, the ACORN devices 124 6.2.5 Spiegel and others at Mitre Corporation 126 6.3 Clues to index-term selection from automatic syntactic analysis 6.4 Probabilistic indexing and natural language text searching 127 132 6.4.1 Probabilistic indexing - Maron, Kuhns and Ray 133 6.4.2 Natural language text searching - Swanson 134 6.4.3 Full text searching - legal literature 135 6.5 Other examples of related research in linguistic data processing 6.6 Machine assistance in translations of subject content indications to special search and retrieval language 6.7 Example of a proposed indexing-system utilizing related research techniques 136 140 142 7. Problems of evaluation 143 7.1 Core problems 145 7.2 Bases and criteria for evaluation of automatic indexing procedures 149 7.2.1 The Cranfield project 150 7.2.2 O'Connor investigations 151 7.2.3 Questions of comparative costs 153 7.2.4 Summary: potential advantages as bases for evaluation 156 7.3 Findings with respect to inter-indexer and intra-indexer consistency 7.4 Special factors and other suggested bases for evaluation 157 160 8. Operational considerations 164 8.1 Questions of input 164 8.2 Examples of processing considerations 168 8.3 Output considerations 171 9. Conclusion: Appraisal of the state of the art in automatic indexing 173 v