UNITED STATES DEPARTMENT OF COMMERCE • Maurice H. Stans, Secretary
NATIONAL BUREAU OF STANDARDS * Lewis M. Branscomb, Director

Automatic Indexing:
A State-of-the-Art Report

Mary Elizabeth Stevens
Center for Computer Sciences and Technology
National Bureau of Standards
Washington, D. C. 20234

National Bureau of Standards Monograph 91
Issued March 30, 1965
Reissued with Additions and Corrections (See Preface), February 1970
For sale by the Superintendent of Documents, U.S. Government Printing Office,Washington, D. C. 20402 (Order by SD Catalog No. C13.44:91), Price $2.25v

Foreword(1970 Edition)Widespread interest in the use of computers in automatic indexing created a demandfor this publication that led to a recent exhaustion of all stock. While updating and revision
would have been desirable, other demands have prescribed reissuance with additional material added as appendices. These are a paper updating the field through September 1966
(Appendix B), and bibliographic citations, pertinent to the subjects in the original text,
through August 1969 (Appendix C).
Lewis M. Branscomb
Director

Library of Congress Catalog Card Number: 65-60023

Foreword(1965 Edition)
The Research Information Center and Advisory Service on Information Processing,(RICASIP), which is jointly supported by the National Science Foundation and the National
Bureau of Standards, is engaged in a continuing program to collect information and maintain current awareness about research and development activities in the field of information
processing and retrieval. An important responsibility of RICASIP is the preparation ofstate-of-the-art reviews on topics of current interest in various areas of this broad field.
This report is one of a series intended as contributions toward improved interchangeof information among those engaged in research and development in this field. The reportconsiders new uses of machines and automatic data processing procedures for the compilation and generation of indexes to the scientific and technical literature.
A. V. A8tin, Directorin

Contents

1.

2.

Abstract

1Introduction

1

1. 1
1. 2
1. 3

2
1013

Definitions and background
Scope of this study
Derivative v s . assignment indexing

Indexes compiled by machine

14

2. 1
2.2

15

2. 3
2.4
2. 5
3.

Concordances and complete text processing
Card catalogs, book catalogs, bibliographies and subject index
listings prepared by machine
Tabledex and other special purpose indexesCitation indexes
Machine conversion from one index set to another

19252738

Indexes generated by machine - automatic derivative indexing

40

3. 1

KWIC indexes40

3. 1. 1
3. 1.2

41

Applications of KWIC indexing techniques
Advantages, disadvantages and operational problemsof KWIC indexing

3.2* Modified derivative indexing
3.2.1
3.2.2
3. 2. 3
3. 3

3. 4

Title augmentation
Book indexing by computer
Modified derivative indexing - Baxendale's experiments

55
68
68
71
73

Derivative indexing from automatic abstracting techniques75

3. 3. 1
3. 3. 2
3. 3. 375
79

3. 3 . 4
3. 3. 5
3. 3. 6

4.

Page

Auto-condensation and auto-encoding techniques of H. P. Luhn
Frequencies of word n-tuples - Oswald and others
Relative frequency techniques - Edmundson and Wyllys,
and others
Significant word distances
Uses of special clues for selection
Recent examples of mixed systems experimentation

Quality of modified derivative indexing by machine

81
83
84
86
89

Automatic assignment indexing techniques

91

4. 1
4.2
4. 3
4.4
4.5
4. 6
4. 7
4. 891
93
94
97
98
99
100
105

Swanson and later work at Thompson Ramo Wooldridge
Maron's automatic indexing experiments
Automatic indexing investigations of Borko and BernickWilliams 1 discriminant analysis method
SADSACT
Assignment indexing from citation data
Similarities and distinctions among assignment indexing experiments
Other assignment indexing proposals

Automatic classification and categorization

Page
106

5. 1
5. 2
5.3
5. 4108
110
113
113

Factor analysis
The theory of clumps
Latent class analysis
Examples of other proposed classificatory techniques

Other potentially related research

114

6.1
6.2

Thesaurus construction, use and up-dating
Statistical association techniques

114
118

6.2.1
6. 2. 26. 2. 36. 2. 4
6. 2. 5119
119122124
126

6.3
6.4

6. 5
6. 6
6. 7

Devices to display associations: EDIAC
Statistical association factors - Stiles
The association map - Doyle and related work at SDC
Work of Giuliano and associates, the ACORN devices
Spiegel and others at Mitre Corporation

Clues to index-term selection from automatic syntactic analysis
Probabilistic indexing and natural language text searching

1271326.4. 1
6.4. 2
6. 4. 3

Probabilistic indexing - Maron, Kuhns and Ray
Natural language text searching - Swanson
Full text searching - legal literature

133
134
135

Other examples of related research in linguistic data processing
Machine assistance in translations of subject content indications
to special search and retrieval language
Example of a proposed indexing-system utilizing related researchtechniques

136
140
142

Problems of evaluation

143

7* 1
7. 2

Core problems
Bases and criteria for evaluation of automatic indexing procedures

145
149

7.2. 1
7.2.2
7.2.3
7.2.4

150
151
153
156

7. 3
7.4

The Cranfield project
O'Connor investigations
Questions of comparative costs
Summary: potential advantages as bases for evaluation

Findings with respect to inter-indexer and intra-indexer consistency
Special factors and other suggested bases for evaluation

157
160

Operational considerations

164

8.1
8.2
8• 3

164
168
171

Questions of input
Examples of processing considerations
Output c ons ide rations

Conclusion: Appraisal of the state of the art in automatic indexing

v

173

Page
Acknowledgments

182

Appendix A:

List of references cited and selected bibliography

183

Appendix B:

Progress and prospects in mechanized indexing

223

Appendix C:

Selective bibliography of additional references

237

vi