ASLIB CRANFIELD RESEARCH PROJECTREPORT ON THE FIRST STAGE OF
AN INVESTIGATION INTO THE COMPARATIVEEFFICIENCY OF INDEXING SYSTEMS- by C. W. CLEVERDON

An investigation supported by a grant to ASLIB
by the National Science Foundation

The College of Aeronautics,
Cranfield, England
September, 1960

CONTENTS
Page
Preface
Introduction
General objectives of theinvestigation

3

Chapter 3

General organisation of programme

20

Chapter 4

Detailed analysis of the problems
encountered

30

Chapter 5

Supplementary procedures

77

Chapter 6

Statistical details

95

Chapter 7

Supplementary indexing

107

Chapter 8

Conclusions117Chapter 1
Chapter 2

References
Appendix A

120

List of project documents
14001 - 14100

122

Appendix B

U . D . C . Schedules and index

132

Appendix C

Alphabetical subject heading

142

Appendix D

Facet schedules

145

Appendix E

List of uniterms

154

Appendix F

Sample sheet of documents forexternal indexing and questions

155

List of co-operating organisations

156

Appendix G
Figures

1-3

165

PREFACE
It was in 1953 that the train of events started which brought about
my participation in the investigation which is the subject of this report.
R.G.Thorne, of the Royal Aircraft Establishment, and I had beenclosely associated with the development of the Nationaal Luchtvaartlaboratorium Card Catalogue of Aerodynamic Data (Ref. 1). This was
an index designed for the retrieval of information in answer to very
specific requests, and was far removed from the systems used inconventional library indexing. In that the average time taken to index
each document was l\ hours, it was comparatively expensive, although
the cost was shared out on a subscription basis amongst a number oforganisations.

Clearly, however, such an index could only be usedfor a relatively limited range of documents that were of particularsignificance, and Thorne and I were prepared to accept the possibility
that in certain circumstances an organisation might be economicallyjustified in maintaining two different types of indexes covering an
overlapping range of documents.

The Universal Decimal Classification

was widely used in England and, in spite of many c r i t i c i s m s , was on
the whole meeting the requirements of its users for a general indexing
system.

We were looking for another system which would fulfil thesame function as the NLL scheme, but which might be less expensive
and therefore more attractive economically for a single organisation
to operate.
At the meetings of the Documentation Committee of the Advisory
Group for Aeronautical Research & Development to N. A . T . O . , we
had reports from the two American m e m b e r s , Mr.K. Lowry and
Mr. E.Jackson, of the developments in the United States. In particularwe heard of the work of Mr. Calvin Mooers and also of Dr. Mortimer
Taube, whose Uniterm system appeared to have possibilities offulfilling our requirements, and we decided to do a small test on thissystem.

This, in the first place, consisted of my indexing 200 reports

in the field of aircraft structures, and carrying out tests based onquestions compiled by Thorne.

The report on this work (Ref. 2) waswritten mainly with the intention of publicising the Uniterm system inEngland, in the hope that other people would be sufficiently interested
to t r y it.

Later we indexed a further 800 r e p o r t s , but this time thetest results were less encouraging and we did not continue ourinvestigations with this system.
Meanwhile we were concerned in devising test procedures, inparticular with the NLL card catalogue (Ref. 3), and by this time I
had become convinced that the only way to obtain a valid comparison
between systems would be to control conditions in such a way that there
was an economic basis for the comparison.

At the Conference of theAslib Aeronautical Group in 1955 I read a paper (Ref. 4) in which, forthe first time, the necessity for controlled experiments was put forward.
This conference was held jointly with the Classification Research Group,a small group of enthusiasts who, with B.C.Vickery as s e c r e t a r y andB . J . Palmer as chairman, met regularly to discuss problems ofclassification, in particular facet classification.

They were the foremostand probably the only group in England who were considering theseproblems, but in America at this time there were a number of groups
actively engaged in proposing new systems and methods.

It was clearthat claims were being made by proponents which, while possibly c o r r e c t ,could not be considered proven by results; just as clearly many of
the arguments being used by opponents of the systems were equallyunproven or trivial.

It seemed desirable that a serious investigation

should be made so that opposing claims could be evaluated, and by
this time we had definite views as to how such an investigation could
be carried out.
In June 1955 I was invited to take part in a Symposium on
Information Retrieval Systems at a meeting of the Scientific andTechnical Division of the Special Libraries Association Convention
in Detroit.

Shortly before this meeting, there had been an interesting

leader in American Documentation (Ref. 5), and, in the SLA paper,taking as a text an extract from this leader, I made a plea that someindependent work should be done in the States to evaluate the rival
claims.

After the meeting, M r s . Helen Brownson, of the National

Science Foundation suggested that, if we would prepare a detailed
proposal, it could be submitted to the Foundation with an application
for a grant.
This suggestion was considered by the Aslib Aeronautical Group,a sub-committee of which prepared the first draft of the proposal,
which was then reviewed by a special committee appointed by theCouncil of Aslib, and with some minor alterations was sent to theNational Science Foundation in 1956. Originally the limit of our hopes
was that the Foundation might be willing to make a contribution towards
the cost, and it was a pleasant surprise to be told that the Foundation
were willing to consider an application for the total sum of 28,000 dollars
to cover the expenses involved in preparing the indexes.

Few people can have received so much co-operation and assistanceas I have had in the project.

First and primarily acknowledgements

are due to the National Science Foundation for their generous financial
support and to Mrs. Helen Brownson, of the Foundation, whose particularresponsibility the project has been, and who has throughout done everything possible to assist the work.

Next I must acknowledge my debt tothe Principal and the Senate of the College of Aeronautics for permitting
me to undertake the project, and also to those members of my librarystaff who have had to suffer the inconvenience of the project work goingon in their midst.
Closely associated with the project from the start have been themembers of a special committee appointed by the Council of Aslib,and Mr. B.C.Vickery, Mr. J . F a r r a d a n e , Mr. K.Lowry, Mr. R . C .
Wright and Mr. C.Hanson have all been generous in the time and thought
which they have given in helping us with our problems.

To my friends

in the Aslib Aeronautical Group I am particularly ^rateful, not only for
their general suggestions and ? criticisms, but also for the work of theClassification sub-committee in revising the aerodynamic sections ofthe U. D. C.

From the start I have at all times had the fullest supportand encouragement from Mr. L.Wilson, Director of Aslib, and I am
grateful for his assistance which has made the administrative aspectsof the project so easy for me.
There are many others whom I should mention and in particular those,
many unknown to me personally, who helped us by compiling questions
for the test programme or by doing supplementary indexing.

Finally, I would acknowledge the work done by the full-time m e m b e r sof the project staff, Miss Warburton, Mr. J . S h a r p and Mr. J.Hadlow,
and in the first few months, Mr. T.Opatowski.

It was a particularly

fiendish form of torture to have to index continuously against a stopwatch, and it demanded the highest personal integrity to work consistently under these conditions.

Throughout the whole two years of thisstage of the project I received the fullest support from the staff whocheerfully and loyally undertook every task demanded of them.

It hasbeen my pleasure and privilege to work with such a team.
This report is basically a factual account of the first stage of theproject, but it was felt that every facet of the experience gained should
be set down, whether it be a statement of fact or the philosophy of aparticular problem as seen by the indexers.

Since their experiences

are virtually unique, it is reasonable that their observations should berecorded, even though no solution to particular problems can beoffered.

In the preparation of the report, Mr. Sharp has given muchassistance, and most of Chapter 4 in particular is as he wrote it.

T.

„. .
n
The College of Aeronautics,Cranfield.
August, 1960.

C. W.Cleverdon