"The differentiation that is made between the two types of indexing is that word
indexing is inextricably tied to the words in a text: If a word appears it getsindexed as such; if it does not appear it does not get indexed. Concept indexing, on the other hand, has an element of abstraction in it: Words may either
be indexed as such or may be converted, either by themselves or in combination
with other words, into concepts which may not bear a.direct resemblance tothe words or combinations of words that evoked them in the indexe^s mind. "Machine techniques such as those of Luhn's KWIC, like the early Uniterm systems,
look no farther than the words used by the one author himself. Techniques such as thoseof Maron, Swanson, Borko, Meadow and Williams, among others, look specifically torelationships between words as used by one author to patterns of word usages in a given
subject area or given document collection. They may also look to these patterns as inturn related to prior human analytic judgments of the "ab outness" referrents of items in
the collection. In this sense, they at least attempt replication by machine of assignment
indexing.
There is no real question but that machines can in fact derive words from text provided that it is in machine-readable form. This machine procedure may involve direct
extraction of all words as index entries, as in a complete concordance. It may involvethe extraction of only those words which survive a "purging11 operation in which articles,
conjunctions, adjectives, and other "common11 words are first deleted. Various machinecontrolled modifications to such "derivative" indexing are also available. The case formachine achievement of assignment indexing for any but limited special cases is not soclear.
2.

INDEXES COMPILED BY MACHINE

A first and obvious use of machines in indexing processes is in the manipulation ofindex entries, previously selected on the basis of human analysis, to produce various
orderings, duplications and listings of these entries. The power of machine techniquesto speed and economize the sorting, ordering and listing operations in the preparationor compilation of indexes was recognized quite early, both in the field of library scienceand in the consideration of potential areas of application by specialists in machine
potentialities.
In particular, two specialized types of index, at least in the broad sense, are suchthat their compilation would be almost prohibitive in terms of time and cost were it notfor the use of machines. These are, respectively, the case of the complete index, theindex to all words of a text in their various contexts, which i s a concordance, i / and thecase of the "citation index", which has been used in the field of law for many years but
has only quite recently been suggested for literature search purposes related toscientific and technical information.

U
See, for example, Doyle,1963 [ 1 6 2 ] , . . p. 11: "Without data-processing
machinery, concordances are prohibitively expensive to generate for most u s e s
except in those cases where it is well known that a given volume of text is going
to be used again and again, by large numbers of people over a long period oftime. As we know, clergymen have made use of manually prepared concordancesof the Bible since the 12th century".

14

In machine-compiled indexes, no item or entries are eliminated by the machine,whereas in even the most rudimentary of machine-gene rated indexes, such as KWIC,
various reductive or extractive operations are automatically applied as a part of themachine procedure. We shall be concerned in this section with brief discussions ofmachine-compiled indexes and related devices, specifically, concordances, card or bookcatalogs mechanically prepared, citation indexes, and special indexes such as Tabledex.
The use of machines to compile, sort, duplicate and list index entries can only be considered to be mechanized indexing in a relatively trivial sense. We shall consider, there
fore, only a few representative examples, emphasizing early work and some of thepioneering instances.
2. 1 Concordances and Complete Text Processing
When as early as 1856, Crestadoro proposed the use of permutations of the words intitles as a subject-content index the only "machines 11 available for the processing operations were people acting in a strictly clerical way. Precisely such clerical operations
have been used for centuries in a process that i s , in the special sense of full representation of document contents, an index-producing operation--the making of concordances.!./
The task of listing each separate word in a book in all the contexts in which it appears
is incredibly time-consuming and tedious when carried out by manual means. There arethose who have spent the major part of their lifetimes at this task. For example: "It.
took James Strong thirty years to compile his exhaustive Concordance of the Bible. . . " —The use of machines capable of processing signals which represent and preserve information offered a potentially revolutionary change, and with the advent of the electronic
computer even more radical possibilities of very high speed processing were opened up.
As early as 1949, J. W. Mauchly (the co-inventor of ENIAC and UNIVAC) envisioned
the use of computers for documentation and library science activities. He suggested thatthe full information contents of the Library of Congress collections could be recorded inmachine language, stored in this form on magnetic tape, and searched by machine in aprocedure which would match words or other selection indicia occurring in the recorded
information to the specified words or selection criteria of a query or search prescription.
Specifically, he estimated that the entire collection, then amounting to 10,000,000 books,
could when transcribed to binary-code representation Jj/ be serially searched in 20
hours. £'T7
See, for example, Black, 1962 [ 6 5 ] , p. 314: "The oldest book in the world has had
such an index for many y e a r s - - t h e concordance to the Bible;" Markus, 1962 [ 3 9 4 ] ,p. 19: "The ultimate in permutation for indexing is a published concordance;" Linder,
I960 [ 363] , p. 99: "We know of a concordance prepared in the 13th Century;"
Simmons and McConlogue, 1962 [ 5 5 5 ] , p. 3: "Complete indexing has been used ofcourse for centuries in the preparation of concordances. "liCarlson, 1963 [ 1 0 1 ] , p.211.

I!
That i s , markings which have one of two values (thus, binary digits or "bits"), canbe used to distinguish between 2 n different other symbols such as alphabetic
characters by using log 2 n of such markings. A binary code for the 26 letters of the
English alphabet requires a five-bit representation for each letter. If numeric digit
characters are also recorded, (26+10), a six-bit code representation is required.

±1
Mauchly, 1949 [ 4 0 6 ] , p. 295. See also "Report to the Secretary of Commerce on theapplication of machines. . . " 1954 [620], p. 67.
15

Mauchly's suggestion was, in effect, the idea of a complete index that could besearched by machine. We should note, however, that although subsequent technologicaladvances could significantly decrease his original time estimate, the crucial questions
that remain are those of what, assuming one-to-one representation of document text, one
would search for. 1 / Natural language searching by machine, in the sense of full text
inspection, is a "pay-as-you-go 1 ' concordance technique. It i s , however, a techniquewhich must be aided and abetted by various forms of synonym reduction, syntactic
normalization, homograph resolution and other special processing operations if it is to bein any sense an effective tool for selection of clues to be retrieved.
Gardin, in a s e r i e s of recent lectures on automatic documentation, (Gardin, 1963
[207, 208] )U refers to the opinions of some investigators that it should be possible to"jump11 the stage of indexing and to aearch the natural language texts directly. The
problem, he points out, then shifts to the determination of all the various ways in which
the possible answers to a question may have been expressed in these natural language"complete indexes". Instead of carrying out reductions or condensations of the documents,
as in normal indexing procedures, amplifications of questions are required. "Reductive"indexing of the source documents can only be eliminated at the expense of "expansive"indexing of questions. Gardin concludes that the gain from this is very doubtful.
There is also the presently staggering burden of time and cost to convert full texts tomachine-usable form. As of February, 1961, it was estimated that the natural language
text material available for machine processing amounted to little more than the words
contained in the Harvard Classics five-foot shelf (Stevens, 1962 [567] ). Perhaps up to
ten times that amount is now available, notably in the 6, 000, 000 words of the statutes ofPennsylvania 3/ and in several million additional words that have since been keypunchedat the Center for Automation of Literature Analysis, G alia rate, Italy. 4/ A very recently
1/See, for example, Yngve, 1959 [ 6 5 7 ] , pp.978-979: "We will have to find formal
connections between widely divergent ways of saying essentially the same thing. In
addition there is much that we will have to learn about searching. If we had today acomplete grammar of English which was capable of rendering explicit all the relations
and distinctions implicit in the document, I doubt that we would know how to use it
effectively in a machine search situation. We would be embarrassed by the very
wealth of the information available. Much more must be learned about searchsituations. "Z!
See also Bar-Hillel, 1962 [ 35] , p. 415: "Could not the stage of clue assignment becompletely skipped and the request topic be directly compared with the original
documents? It is very natural that such a thought should have arisen, but it must
be stressed that there is nothing in our knowledge of the workings of communication
which would indicate that such a proposal i s , or ever will be, practical. "See various references by J. F. Horty, W. B. Eldridge and S. F. Dennis, E. M. F e l s ,R. Wilson.

±1
R. Busa, data reported at the NATO Advanced Study Institute on Automatic Document Analysis, Venice, July 1963.

16

completed study made by the TRW Computer Division, Thompson Ramo Wooldridge,
involves the investigation of the possibilities for a center to provide text in machineusable form. The report gives a total figure of approximately 50, 000, 000 words of text
so available as of February 28, 1964, but this includes non-scientific text, such as newspaper and popular magazine materials (Mersel and Smith, 1964 [ 4 1 5 ] ).
Mersel and Smith also report on the estimated requirements for machine-usable text
for various research groups, averaging over a million words per year per group. Yet, atpresent keypunching costs of one cent or more per word, iB it reasonable to assume thatany of these research groups can provide a budget of over $100, 000 per year for thispurpose alone? Moreover, this budget would provide for the conversion of no more thana thousand 1, 000-word items .or a hundred 10, 000-word items at costs, respectively, of$100 or $1,000 per item. For the present, therefore, the conclusion is inescapable: either
indexing or search based upon full text processing i s not yet practical. Even the mostenthusiastic proponents of "searching full natural language text11 (Swanson, I960 [ 589])
and "maximum-depth indexing*'(Simmons and McConlogue, 1962 [ 5 5 5 ] ) generally agree asto the present impracticality of full-text mechanized indexing except for special limited
cases.
The two problems of determining what to search for, given full text, and of feasibilityof conversion of text into machine-usable form thus combine to limit "complete indexing"
largely to the special cases of providing corpora for studies in the field of computational
linguistics and of compiling the traditional scholarly tool--the concordance to all the words
in a given literary work or works. Apparent exceptions, including experimental workwith abstracts only and the law statutes studies, are usually cases in which the selective
principle of disregarding common words (and hence the bulk of the actual text) is applied
automatically either on input or in subsequent processing (Cleverdon and Mills, 1963
[ 1 3 1 ] ) . These c a s e s , therefore, m a y b e considered machine-generated indexes rather
than machine-compiled. Moreover, it should be noted that:"

The law, itself, is an appropriate field for data retrieval. The statutes,
especially, are written in relatively clear, concise language. At least, thisis their intent. Practically, this means that input and output can both berelatively short and that retrieval of legal information will be involved withfewer semantic difficulties.

In the area of concordance-making, however, the potentialities of machine compilation have been put to good use. The pioneer efforts in this area are unquestionably
those of Father Roberto Busa, S.J. , of the G alia rate Center. As early as 1946, Busa
proposed to his superiors that a card file recording all the words used in all of the worksof St. Thomas Aquinas should be set up, and he began his actual experiments using IBM
punched card equipment in 1949 (Busa, 1953 [ 8 7 ] , I960 [ 9 l 3 , and 1958 [ 9 2 ] ; Secrest,
1958 [ 5 4 0 ] ). 2 / Appearing in 1951, his Sancti Thomas Aquinatis Hymnorum Ritualium
Varia SpeciminaConcordantiarum is the first known example of a complete word index
that was compiled by machine techniques. The early Gallarate work was carried out onstandard punched card equipment, but from the time of the concordance to the Dead Sea
Scrolls, computers have also been used (Tasman, 1959 [ 5 9 5 ] , [ 5 9 6 ] , anjd[597] ). The
major continuing task i s still to other works of St. Thomas. Other machine-compiled
concordances produced by Busa's Center include one to Goethe's Farbenlehre, Bd. 3.

17"
Asher and Kurfeerst, 1963 [ 2 4 ] , pp.1-2.

U
See also Scheele(ed.), 1961 [522], pp-206-209.
17

Other relatively well-known examples of machine-compiled concordances include
those to the Revised Standard Version of the Bible (Ellison, 1957 [ 186]; Cook, 1957 [ 139] )and to Matthew Arnold's poetry (Painter, I960 [ 4 6 l ] ; Parrish [467, 468] ). The Cornell
Concordance Series, under the general editorial supervision of Parrish, includes investigations of Old English, such as The Anglo-Saxon Poetic Records (Bessinger, 1961[59]).
The November 1962 issue of Current Research and Development in ScientificDocumentation, No. 11, [ 4 3 0 ] , lists several concordances compiled by machine including
the work of Sebeok [ 5 3 3 , 534] and associates at Indiana University on Cheremis folksongs,
the work on the National Vocabulary of the French language under Quemada at the
University of Besancon, U the preparation of glossaries and concordances to the works ofKant at the University of Bonn 2j $ and concordances to medieval German texts being
compiled by Wisbey at the University of Cambridge (Wisbey, 1962 [ 6 4 6 ] , [ 6 4 7 ] ). At the
University of Gothenburg in Sweden, work has begun on mechanical linguistic analysis ofEnglish language texts, using the machine-readable teletype setter tapes used for the
printing of paperback books (Ellegard, I960 [184] and 1962 [185] ). ±' Another recent
example is that of the work at the Summer School of Linguistics, University of Mexico(Grimes and Alvarez, 1961 [ 2 4 3 ] ). By 1963, Marthaler writes that ff Compiling concordances with the aid of a computer is already standard routine to such an extent thatit needs hardly be described in detail. n £ / As of January 1964, a general-purpose computer program for the IBM 7090 which can compile various types of concordances has
been announced as available from the Mechanolinguisties Project at the University ofCalifornia. (1964 [ 9 5 ] ). 51
The major advantage of using machines to compile concordances i s , of course, theenormous difference in the time required to complete the work. Thus, only 120 hours
were required on the UNIVAC computer to prepare the 800,000 words of the Concordance
to the Revised Standard Version of the Bible (Cook, 1957 [ 139]; Ellison, 1957 [ 186] ) . i Z
1/
See "Actes du colloque sur le mecanisation. . . ", 1961 [ l ] ; Quemada, 1961 [ 4 8 5 ] and1959 [ 4 8 6 ] ; Centre d'Etude du Vocabulaire Francaise, "Specimens de Travaux
lexicographiques. . . fl, I960 [ 106].

u
National Science Foundations CR&D Report No. 11 [430] p. 316

1'
Ibid, p. 321.

±1
Marthaler, 1963 [399] , p. 14

I'y"California Concordance Program Available f M964 [95]Carlson, 1963 [101] , p. 211.

18

In the u s e of the IBM 705 for the concordance to the Summa Theologiae, F r . Busa r e p o r t s
that only 60 hours w e r e required to a r r a n g e in alphabetical o r d e r 1, 600, 000 w o r d s . U
This advantage of speed, with the concomitant benefits of both economy and t i m e l i n e s s , isillustrated by Tasman as follows:" . . . It has been estimated that it would take 50 scholars 40 y e a r s . . . to manuallyindex the 13 million or so words of St. Thomas Aquinas 1 complete w o r k s . IBM
punched card machines would produce the indexes and concordances much m o r eaccurately and would take ten scholars about four y e a r s . L a r g e - s c a l e datap r o c e s s i n g techniques would reduce the time to about 25 percent. . . (or). . . tens c h o l a r s to do the job in l e s s than a y e a r . " zlOther advantages s t e m from the facility with which further machine processing can be
introduced. Once the text is in m a c h i n e - r e a d a b l e form, a number of valuable byproducts
can be derived. Examples a r e s t a t i s t i c s on the number of words that have 2, 3, . . . n
l e t t e r s , frequencies of l e t t e r usage; printouts*of o c c u r r e n c e s of specified words or groups
of w o r d s ; and l i s t s alphabetized on t e r m i n a l r a t h e r than initial l e t t e r s . Added advantagesof computer p r o c e s s i n g a r e further exemplified in the options available with the California
concordance computer p r o g r a m (1964 [ 9 5 ] ) , some of which a r e as follows:(1)

The u s e r may obtain a r e s t r i c t e d r a t h e r than a full concordance by supplying alist of words for which no entries a r e to be m a d e .

(2)

The u s e r may obtain a selective concordance by supplying a list of words forwhich, and only for which, e n t r i e s a r e to be m a d e .

(3)Each entry word may be centered with its preceding and succeeding context,
up to the limits of one full line of 131 c h a r a c t e r s , or each entry word may belisted together with the full sentence or v e r s e in which it o c c u r s .

(4)

Text with interlinear information such as g r a m m a t i c a l symbols can be used andselective concordances can be compiled on the b a s i s of such interlinear
information.

(5)

The citations of an entry can be listed in o r d e r of textual o c c u r r e n c e , in ano r d e r determined by preceding or following words in its context or in an o r d e rdetermined by accompanying i n t e r l i n e a r symbols.

2 . 2 Card Catalogs, Book Catalogs, Bibliographies and Subject Index Listings
P r e p a r e d by Machine
The u s e of machines such as punched c a r d equipment for the preparation and p r o cessing of l i b r a r y card catalogs and of index listings was advocated by a few far-sighted
documentalists at l e a s t as early as the 1930's ( P a r k e r , 1938 [ 4 6 3 ] ; Dewey, 1959 [ 1 5 3 ] ) .

y
See his statement in Scheele, 1961 [ 5 2 2 ] , p . 209.

y
Tasman, 1958, [596] , p. 11.

19

McCormick's bibliography on mechanized library processes (1963 [ 4 0 7 ] ) lists a numberof early suggestions, notably those of Fair in 1936 C 187], Shera in 1938 [ 5 4 7 ] , and Gates[ 2 2 5 ] and Callander [ 9 6 , 97,98] in 1946, Cox, Bailey and Casey proposed the use ofpunched card equipment for the preparation of bibliographies in the field of chemistry in1945 [ 1 4 2 ] .
By 1946, Gull claimed that:11. . .Punched cards and present equipment offer new possibilities right now forsolving the problems of the indexes to Chemical Abstracts. These indexes arelarge undertakings in themselves, and the work of arranging, cumulating, andprinting them can be simplified by placing the index information on punchedcards at the time the abstracts are made. With current indexes on punchedcards, two or three cumulations of the author index during the year will greatly
reduce the work required in using current i s s u e s from that approach. Cumulations of the subject, patent, and formula indexes immediately become possiblefor intervals more frequent than once a y e a r . ! l [ 2 4 5 ]The following year (1947) saw a summary by Gull of potential applications of punchedcards in special libraries [ 2 4 7 ] , and Becker surveyed some of the then discernible
prospects for library mechanization, as a student in the Library School of Catholic
University. He stressed such advantages as flexibility in the processing of new material
for abstracting, indexing, filing, and interfiling purposes and the printing out of various
listings in any format. zJ
The potential use of machines for library science and documentation had not actually
been recognized, however, for many years after the invention of punched card equipment.
Both the punched card developments (beginning with Hollerith and Powers in the 1880's)
and the electronic computers developed from 1946 onward were first applied to the automatic manipulation of information in the sense of statistical, mathematical, or engineering data, rather than to information about data or information about other information.
Dr. John Shaw Billings, himself a librarian of: note, was apparently the first to suggest
to Herman Hollerith the idea of recording information as holes punched in cards which
could then be sorted mechanically. 2J. Larkey comments: "It is not known if Billings everthought of applying the principle to bibliographic work, but it would seem eminently
fitting that it might be so utilized. f l 1 /Larkey himself as head of the Army Medical Library Research Project at the Welch
Medical Library, Johns Hopkins University, was certainly one of the pioneers in such
utilization, but this was almost 70 years from the date of the Billings-Hollerith
conversations. The Army Project, begun in late 1948 or early 1949, had as its contract

T7
Becker, 1947, [ 4 3 ] , pp. 11-12: "From the flexible arrangement of the cards,
bibliographies become readily available by subject, author, and title. In special
libraries, where material on one subject is concentrated, the research possibilities
of gathering, sorting, filing, and printing information are almost limitless. Continuous machine interfiling permits keeping current with new entry additions. nU"With the m a s t e r s . . . " , 1963 [ 6 4 8 ] , p. 18.
Larkey, 1953 [ 3 5 l ] , p. 34.

20

objective "to explore existing and projected methods, emphasizing machine methods,
applicable to such pilot projects as may be necessary 11 (Larkey, 1949 [348], 1956 [ 349],
and 1953 [351] ). Also as of 1949, the Library of the Department of Agriculture isreported to have f, conducted an experiment in the use of electronic data-processing
machines to produce the author and subject indexes to the 'Bibliography ofAgriculture 1 . " W
It is not until the early 1950 f s, however, that punched card machine techniques wereactively put to use for the preparation of card catalogs, book catalogs, bibliographies andvarious index listings. Then, a number of independent but largely concurrent applications
were tried out on at least an experimental basis, including in addition to the work of the
Welch Medical Library Project pioneering efforts in mechanized book catalog production(Griffin, I960 [ 2 4 2 ] ; Martin, 1953 [ 400]; Berry, 1958 [ 5 8 ] ) and what is claimed to be the"first successful n on-experimental punched-card catalog of periodicals", the Serial Titles
Newly Received (now New Serial Titles), as published by the Library of Congress from1951 onwards. ? /The work at the Welch Medical Library continued for several years, the final reportbeing issued in 1955 [ 2 3 4 ] . Beginning in 1951, the project maintained in punched card
form the subject heading authority list used for the Current List of Medical Literature(Larkey, 1953 [ 3 5 l ] ; Garfield, 1953 [217] and 1954 [ 2 2 0 ] . " Garfield has stated that thiswork "clearly demonstrated the ease of converting alphabetic subject heading lists tocategorized or classified lists of terms by the use of punched card .equipment." 3/That i s ,each heading or subheading had assigned to it a numeric code reflecting its appropriate
position in the classified system, which could then be used by machine for sorting,ordering and listing. Ingenious use was made of the IBM 101 Statistical Machine in the
preparation of printed subject indexes (Garfield, 1953 [218] and 1954 [ 2 1 6 ] ) . Other
subject heading lists maintained by punched card techniques by 1953 or earlier included
those of the U. S. Patent Office and the Technical Information Division of the Library ofCongress..!'
The first loose-leaf printed book catalog to be produced by machine methods wasapparently that of the King County Public Library in the State of Washington in 1951, andthe following year the Los Angeles County Library inaugurated a similar system for the
distribution of a master book catalog prepared by mechanized techniques (Berry, 1958
[ 5 8 ] ; Griffin, I960 [242] ; Martin, 1953 [ 400]; Alvord, 1952 [ 4 ] ) .
The work on mechanized preparation of lists of periodicals at the Library ofCongress has been reported as follows:"In 1951, the Library began publishing, at monthly intervals, Serial Titles
Newly Received. In 1953, its title was changed to New Serial Titles. . .
Ever since its inception, the fundamental ingredient of the publication has
been the IBM punched card. . .

J7

I)

U.S. Congress, Senate Committee on Government Operations, I960[619] t p. 147.
Dewey, 1959 [153] , p. 36.

u Garfield, 1959 [221] , p. 471.
4/

Garfield, 1954 [220] , p. 1.
21

n

Two important advantages of the punched-card method were foreseen when the
publication began. First, it would be possible to print lists from the cards at will,
without any further editing or proofreading, once the information was in punched-card
form. Second, there was the possibility of mechanically preparing special lists of
titles, selected on the basis of subject, country, or language. " 1 /Thus, by 1953, fl a number of instances of printed indexes prepared by machine 11 could
be claimed. 2 / The use of punched cards to sort, to prepare tabular listings for various
drafts and revisions, and to interfile corrected or revised entries greatly facilitated the
preparation at Battelle Memorial Institute of the subject index to the Proceedings of theInternational Conference on the Peaceful Uses of Atomic Energy, 1955 (Lipetz, I960
[367]).
Developments in the use of punched card machine techniques in bibliographic operations of these types, beginning in the 1950's, have by no means been limited to the UnitedStates. For example, Remington Rand punched cards have been used in the preparation ofa national union catalog of Italian libraries,
and Mikhailov reports for the All-Union
Institute of Scientific and Technical Information (VINITI) as follows:"The development program for machine production of indexes has been underway
at the Institute for a number of years. . .In fact, operational use of Soviet-madepunch-card machines to compile the author indexes for some of the series of our
Abstract Journal has been practiced at the Institute since 1957, l f Zft

In France, at the Centre d'Etudes Nucleaires, Saclay, a program has been developed
for mechanization of the production of biweekly and cumulative indexes and for demand
searches (Chonez, 1 9 6 0 [ l l 6 , 117, 118]).
With the advent of automatic data processing s y s t e m s , the speed, the flexibility andthe capability for multiple-purpose processing buttress the claim that the card catalog canbe "replaced or supplemented by book catalogs made with the aid of mechanized equipment". — It is further claimed that "The printed catalog produced by means of automatic
equipment combines the best features of the conventional card catalog and the traditional
printed catalog, and adder to both new dimensions that would have been unbelievable a
generation ago. " z! A joint project is under way by the Medical Libraries of Columbia,

TJ
U.S. Congress Senate Committee on Government Operations,

I960 [ 6 1 9 ] , p. 85.

uLarkey, 1953, [ 3 5 1 ] , p. 38.

If
Berry, 1958 [ 5 8 ] , p. 287.

±1
Mikhailov, 1962 [ 4 1 0 ] , p. 50.
5/McCormick, 1963 [ 4 0 8 ] , p. 195.

£/
Vertanes, 1961 [ 625], p. 242. This i s with reference to the LILCO Library Printed
Catalog, which is prepared by sorting and processing information on titles, authors
and titles-by-subject-groupings serving as indexes to the holdings at the Long Island
Lighting Company.
22

Harvard, and Yale Universities for corriputer preparation of book catalogs for books
published from I960 onward (Kilgbuf, et al 1963 [ 324]). Another recent illustrative
example of the production of printed book catalogs by means~of computer compilation isthat of the Boeing "SLIP" System (Weinstein and Spry, 1963 [ 633]).
Along with recognition of computer -processing potentialities there has emerged
increased awareness of the desirability of taking advantage of one-time recording of
information to serve multiple purposes: the principle of by-product data generation. The
advantages for the library and document collection are that a single recording of bibliographic information in machine-usable form can lead to a variety of products, specifically
including printed book catalogs, A/ recurrent and demand bibliographies, the requisite
number of copies for conventional card catalogs, card catalog sets or catalog listings forthe personal use of the individual worker, input to mechanized selection and retrieval
systems, and machine-manipulatable data for such other purposes as circulation control.
Turner and Kennedy report, for example, the initial use of a Flexowriter to prepare
library catalog cards and the by-product generation, via a 1401 computer, of bi-weekly
listings of unclassified report titles at the Lawrence Radiation Laboratory, the "SAPIR11
System (Turner and Kennedy, 1961 [ 6 1 5 ] ) . Chasen discusses a change from a previous
punched card, system for circulation and recall at General Electric ! s Missile and Space
Division Laboratory to a combined Flexowriter and G.E. 225 computer procedure toprovide mechanized retrieval, compilation of desk catalogs, computer updating of
catalogs and files, and the maintenance of subscription lists (Chasen, 1963 [ 1 0 8 ] ) .
Fasana describes a system at the Air Force Cambridge Research Laboratory Library
where typing indications in the tape are used as boundary codes. He reports:"Input tapes are currently being processed on a computer to automatically produce
catalog card sets, circulation control records, and book form indexes. Original
input tapes now being accumulated will form the basis of a machine-searchable
file to be used in the future for more sophisticated printouts and searches. "For such applications, Durkin and White make the following typical claims:"The system described has permitted the IBM Command Control Center Engineering
Library to produce its catalog cards and library bulletin both faster and cheaper.
Since a by-product of this process is the preparation of all catalog information inu
See for example, Olney, 1963 [ 4 5 8 ] , p. 42: "During the past few years a numberof libraries have initiated a program of mechanization.. .by punching on IBM cards
or paper tape some of the bibliographic information normally given on catalog cards.
Recording this information in machine-readable form makes it very easy to prepare
printed book catalogs. . . "yFasana, 1963 [ 1 9 5 ] , p. 326. This system involves the "Machine-Interpretable
Natural Format" and procedures developed for AFCRL by Itek Corporation;
see also Lipetz et al, 1962 [ 3 6 8 ] .

23

punched card form, it has also permitted the establishment of a circulation control
system, the publication of overdue notices and reading l i s t s , and the eventual
institution of a computer retrieval program" (Durkin and White, 1961 [ 1 7 3 ] ; White,
1963 [ 6 3 8 ] ) .
Heiliger reports for the library of the new Chicago Campus of the University of
Illinois as follows:"The type of bibliography the computer cam produce does make greater use of LC
card information than do present card catalogs. With the computer programmedwith a set of library filing rules and a set of symbols that describes for the computer
the various parts of the bibliographic unit, it can print-out, for instance, a list ofbooks published in a given country, between certain years, on a certain subject (orcombination of subjects), that are illustrated and have bibliographies. It will also
be possible to permute on individual items in LC subject headings in the same fashionthat Chemical Titles does on titles. This index has been dubbed POSH (£ermuted on£ubject headings). " .1/
Some recent experimental work at Inforonics, Inc. puts major emphasis on byproduct data generation, beginning with the actual preparation of manuscripts for publication. Tape typewriter processing of manuscript for journal articles is being studied
from the point of view of producing machine-usable text. This text, together with coded
identification of the separate items in the text, is so prepared that computer programs
can produce from the single-input automatic typesetting tapes for the article itself,author and subject index entries, and the like. Computer text transformations can also
produce entries for citation indexes, abstract journals and search files (Buckland, 1963
[ 8 3 , 84]).
Other computer-produced indexes or special indexes involving compilation rather
than selection by machine include indexes to Nuclear Science Abstracts (Day and Lebow,
I960 [ 151]), the Current List of Medical Literature (Chonez, I960 [116, 117, 118]),
the Retrieval Guide to Thermophysical Properties Research Literature, —' and the
Research and Development Abstracts of the USAEC (Sherrod, 1963 L 5 4 l ] ) . At theAtomic Energy Commission also, a modification of this RDA computer program is used
for author, corporate author, number and subject indexes for the Engineering Materials
List, which includes announcements of blueprints and drawings.—' In several instances,machine processing capabilities are used for permuted listings under various assigned
indexing t e r m s . ! ' Special c a s e s of machine permutation operations involve compilationand organization of chain indexes, used to reflect the various key entries in facetedclassification systems (Dowell and Marshall, 1962 [ 1 5 9 ] ; Foskett, 1962 [199]; Olney
1963 [ 4 5 $ ] ) .

17
Heiliger, 1962 [ 2 5 9 ] , p. 475.

D
Markus, 1962 [394], p. 19; Touloukian, 1962, 1963 [607] .

U
Davis, 1963 [ 150] p. 237.

±1
See, for example, reports on the SWIFT program for NASA's STAR (Newbaker andSavage, 1963 [438 ] ); the AIMS System (Heller, 1963 [ 2 6 0 ] , and the SPINSTRE
System (Wheater, 1963 [639 J ).
24%$

A final special c a s e of a computer-compiled index should be noted. This i s the workof Schultz and Slierpherdwith reference to the annual meetings of the F e d e r a t i o n of A m e r i c a nSocieties for Experimental Biology (FASEB) (Schultz and Shepherd, 1 1960 [ 5 3 2 ] ; Schultz,
1963 [ 5 2 7 ] ; Shepherd 1963"[545]"n. 1 / The indexing t e r m s a r e generated f i r s t by the authorsof the p a p e r s but a r e then run a g a i n i t a computer p i o g r k m , which by t h e s a u r u s - t y p e lookup eliminates synonyms and supplies syndetic devices in addition to formatting the subject
index for printout.
The m a c h i n e - r e a d a b l e t h e s a u r u s developed for this project presently p e r f o r m s thefollowing four basic functions (Schultz, 1963 [ 5 2 7 ] ) :1.

It accepts words from titles and indicia supplied by the authors without
modification if they m a t c h acceptable indexing t e r m s .

2.

It recognizes certain other words as acceptable if modified and modifies themaccordingly t for example, by "use 11 directions for synonyms and n e a r - s y n o n y m s .

3.

It adds additional indexing t e r m s when certain words occur, an example being
11'penicillin 1 , u s e also 'antibiotics 1 . , f

4.

It deletes certain words if they do not occur in the context of an acceptableindexing p h r a s e .

2. 3 Tabledex and Other Special P u r p o s e Indexes
The u s e s of machine techniques in index compilation so far discussed r e p r e s e n t
instances in which conventional tools of bibliographic control can be p r e p a r e d at lower
cost or m o r e rapidly, or both. In addition, however, certain new and unconventional
types of index have been or a r e being produced with the aid of c o m p u t e r s .
The Tabledex method, as proposed by Ledley in 1958 (Ledley, 1958 [ 3 5 2 ] , Zusman,
et al, 1962 [ 6 6 l ] ; O'Connor, I960 [442]^, involves coordinate indexing in bound bookform, with special features to facilitate s e a r c h , conserve space and display index t e r m s
co-occurring with a given t e r m for a given item. •£/ A major advantage claimed for thismethod is that by the u s e of computers bibliographies and book-form indexes can beorganized, compiled, and printed in page format within a m a t t e r of h o u r s .
A Tabledex index typically consists of a bibliography p r o p e r , in which each citation
has been assigned an identifying number; an alphabetical list of the indexing t e r m s used,
1/
These investigators claim the first production
computer.

of a conventional subject index byi/See, for example, O'Connor, I960 [ 4 4 6 ] , p . 241: "Ledley approximately halves theaverage size of the document descriptions required by imposing an o r d e r on the
vocabulary of indexing t e r m s . When a document description belongs in a t e r m subset,
only those t e r m s of the description need to be r e c o r d e d which come l a t e r in t e r mo r d e r than the t e r m of the t e r m of the subset. This i l l u s t r a t e s another type ofstorage organization. "which may also have numeric codes; and a set of indexing tables. These tables containitem numbers in the leftmost column, and either the names or the codes for indexing
terms assigned to an item along the row. There is one such table for each distinct term
used in indexing the items.
To facilitate searching, only those terms which are of higher numeric or alphabeticorder than that for the term for which the particular table is compiled are recorded in therows. Thus to make a search on several terms, the user turns to the table for the one ofthese terms that has the lowest term value, which table records all items to which theterm has been assigned, and checks the rows of the table for the second lowest ranking
term, the third, and so on. Variations in the Tabledex method allow for the automatic
assignment of numeric codes to the indexing terms based on relative frequency of use
within the collection. Ledley also discusses methods for finding articles associated withall except one, all except two, or all except n of the given words in a searchprescription. IJ
A first example of a computer-compiled Tabledex index was that to a bibliography
prepared by the Library of Congress, for the International Geophysical Year (Zusman
et al, 1962 [ 6 6 l ] ) . zJ The computer program for the IBM 7090 carried out the operationsof assigning accession numbers, extracting index terms and compiling the term lists,
determining frequencies so as to assign frequency numbers to the terms, organizing andpreparing the tables, and developing an author index. Two formats were used, one giving
terms by numeric code and the other spelling out the terms as normal words. The latterfeature provides a measure of browsability in the system. zJ A Tabledex compilation
program is also in use at the Applied Physics Laboratory of Johns Hopkins University(Olmer and Rich, 1963 [ 4 5 4 ] ) .
Another coordinate index search tool, making use of what is in effect a documentdescriptor matrix with special codes and column arrangements to save space andfacilitate rapid scanning, is the Scan-Column Index suggested in 1960by O'Connor [ 4 4 9 ] .
He further suggested the use of computers for compilation, as follows:"A computer can organize information about documents into a scan-column index.
The input needed consists of the document identifications and their accompanying

U
Ledley, 1959 [352], pp. 1235-1239.
See also National Science Foundation CR&D No. 11 [ 4 3 0 ] , pp. 130-131.

I'
Zusman, et al 1962, [ 6 6 l ] , p.ii: ". . . The word tables have the advantage thatbrowsing can be accomplished and possible associations made during the search. . .
Such 'browsing 1 can be enhanced by including at the end of each row in a table all
the other words also associated with the article of that row".

26

index t e r m s . . . and an indication of either the number of columns desired or thecolumn density desired. The computer will determine the frequency of eachterm, the positive and negative correlations of terms, and the quantity of these
correlations by counting or sampling key figures, such as the average number,of terms per document. It then can assign column-character codes accordingly.11—
In 1961, Costello described the use of computer techniques for compilation andcomputer printout of a dual dictionary for a coordinate indexing system using links androles at DuPont's Polychemicals Department. After manual analysis, term-role assignments are keypunched, the cards are listed for editing including the elimination ofsynonyms and the indication of appropriate postings to more generic terms, and r e keypunched for conversion to magnetic tape. Tapes for posting of items and links tot e r m - r o l e s are merged by computer with tapes giving alphabetical equivalents of term
codes and with appropriate syndetic indications for final output on an IBM 407 high-speed
printer [ l 4 l ] .
Still another instance of a coordinate index, modified to show pre-coordination ofterms as compiled by computer, is that ot the Electronic Properties Information Center(Johnson, 1963 [ 3 0 l ] ) . The system consists of abstract cards maintained in accession
number order, together with machine printouts that pre-coordinate descriptors withinnine major categories. The listings of pre-coordinated descriptors are arranged inthree different indexes; alphabetically arranged within each category, alphabetized without respect to category but with code indication of the category reference, and a noncategorized listing arranged alphabetically in reverse order. Advantages of machineprocessing include the ease with which various statistical counts can be made, such as
the average number of items in the system for a given material and a specified property.
Summary indications of the state-of-the-art in the field of interest can be obtained, f, forthe s y s t e m will indicate not only areas where research has been done, but also areas
where gaps in the literature occur, and a measure of the growth of research activities
in the field can be developed. n 2/
2. 4 Citation Indexes"A citation index is a directory of cited references in which each reference isaccompanied by a list of source documents which cite it. " ~J This is a relatively new17
O'Connor, 1962 [ 4 4 9 ] , pp 18-49.

I)
Johnson, 1963 [ 3 0 1 ] , p. 296.

II
Sher and Garfield, 1963 [ 5 4 6 ] , p. 63.

27

type of bibliographic search tool that would be almost impossible to compile without theuse of machines. 1/ In at least one case, moreover, the availability of mechanicaldevices was itself the inspiration for the idea of a citation index to the scientific literature. Garfield states in a 1954 paper that he was led to the idea of "Shepardizing" froman earlier concern with the development of citation codes or f, coden" 2/ that would
facilitate machine processing of bibliographic and index entries.£'
The value of Shepard's Citations in tracking down precedents and decisions has beenrecognized in the legal field for many years. ^J The desirability of a similar tool for
literature searchers in the fields of scientific and technical information was suggested
about a decade and a half ago, when Seidell and others proposed its use for patent
searching (Seidell, 1949 [ 5 4 l ] ; Hart, 1949 [255]). In 1954, the Bush Committee in its
considerations of the potential applicability of machines to Patent Office problems
received a proposal from the Atlantic Research Corporation of Alexandria, Virginia,
which was to cover "the development of a Patent Citation Index, comparable to Shepard's
Citations". jL4n the period 1954-1956, both Garfield £/and Fano I/independently advocatedthe development of a citation indexing tool for scientific and technical literature. As
1/See, for example, Atherton, 1962 [ 2 5 ] , p. 4: "The volume of data to be processedis so massive that processing machines are a necessity"; Garfield 1954 [210], p. 4:"Where such large volume of data is to be handled it must be expected thatmechanical devices of high speed and versatility. . . would probably be a determining
factor in the system's s u c c e s s . "

U
II
±1
1'

That i s , brief codes, often mnemonic, for journal title abbreviations and otherclues to publisher and date of publication.
Garfield, 1954 [ 2 1 0 ] , p. 2.
How to Use Shepard's Citations [28l3 has been published periodically by Shepard's
Citations, Inc. , Colorado Springs, since 1873.
U. S. Dept. of Commerce "Report to the Secretary of Commerce. . . , " 1954 [ 6 2 0 ] ,p> 27.
Garfield [210, 211, 2 1 2 ] . Adair, writing in January, 1955, specifically acknowledges a suggestion of Garfield's (for 1955 [ 2 ] , p. 32) but Garfield in turn credits
Adair, (1963 [ 2 1 4 ] , p. 290).
Fano, 1956 C 191]» p. 3: "L»et us accept, at least for the sake of this argument, theconclusion that linguistic associations between documents cannot lead to a satisfactory definition of a bibliography. Then the only other type of association forwhich evidence is available is that provided by simultaneous references in theliterature, by the concomitant use of documents by experts as evidenced by libraryrecords, and by other similar joint events. M

28

of today, there are at least five or six instances of citation indexes that have been produced, several different Experimentalinvestigations are under way, and new interest
has been generated*by the considerations of the Weinberg P a n e l . Thus:"Of the newer approaches to the indexing of scientific documents, the Weinberg
Panel was particularly impressed with the citation index as a promising bibliography tool* In order to learn more about this approach, the National Science
Foundation is currently sponsoring the compilation and publication of extensive
citation indexes for the fields of genetics and also for statistics and probability;
and is supporting two kinds of experiments to evaluate different techniques forusing citation data in indexes and searching systems in the field of physics.
In general, the principle of citation indexing i s based upon the hypothesis that thebibliographic references cited by an author provide significant clues to the subject content
of the author's own paper and/or that there i s a certain commonality in subject between
papers that cite the same references or that are co-cited. 2 / The principle can be applied
to the compilation of bibliographical or indexing tools in several different ways. First,
there is the method of citedness, which groups for a given item the identifications of subsequent items that have cited it. The converse of this i s , of course, the bibliography orreference list of a given item, 2 / I n the first case, we are concerned with "descendants, n
and in the list of references with "ancestors* 1 . 4/

U

Committee on Scientific Information, 1963, [ 1 3 5 ] , p. 16.

2/

Compare Adair, 1955, [ 2 ] , p. 32, with respect to Shepard's Citations itself:"Since all of the c a s e s listed under a given case have cited it, it follows thatthey must all be, more or l e s s , pertinent to the case cited." See also Kessler,
1963, [ 3 2 0 ] , p. 1: "This method . . . originated in the hypothesis that the bibliography of technical papers is one way by which the author can indicate theintellectual environment within which he operates, and if two papers show similar
bibliographies there i s an implied relation between them."
3/

See Salton, 1962, [ 5 2 0 ] , p.Ill-3: "A citation index consists of a set of bibliographic references (the set of 'cited 1 documents), each being followed by alist of all those documents {the 'citing 1 documents) which include the given
cited document as a reference. A citation index i s to be distinguished from areference index which lists all cited documents under each citing document."
4/

See, for example, Tukey, 1962, [ 6 l l ] , p. 5: "Any user's greatest need i slikely to be for a c c e s s to the latest information rather than to the oldest, but
the latest items are children, not ancestors. Genealogy i s important, but
progress requires tracing descendants lung and Vandeputte, I960, [ 2 9 1 ] , p i l l ,make a similar distinction between "histoire" (antecedents) and "filiation11(successors).

29

A second method, implied in Fano's suggestions for the use of relative frequencies
of association between items found in the literature, i s one of citingness, which groups
together items that cite one or more identical references. This method has beendeveloped by Kessler and his associates as the technique of "bibliographic coupling11(Kessler, [ 3 1 7 ] through [ 3 2 3 ] . The purpose here i s to Identify groupings of related
items where relatedness i s defined in terms of the number of references shared by eachof the members of the group with some given test paper or with each other. It is notedthat where the citedness index and the reference list typically give the bibliographic
references themselves as the searching or retrieval tool, the bibliographic couplingtechnique seeks rather to define groups of similar papers. 1 / A third method, and one
which may be combined with either of the other two, i s to derive indexing terms for agiven paper from the overlay of indexing terms previously assigned to any papers which
it cites. Saltonj!/ further suggests that:n. • • Citation indexes could be used to extend a given set of index terms by
starting with the terms attached to a given document or document set, andadding to them the 'related 1 terms obtained from new documents which cite
the original o n e s . "The suggested advantages of citation indexing include the claims that this tool does
not require trained indexers, $J that it i s highly susceptible to mechanization (Garfield,
1955 [ 2 1 3 1 1956 [ 2 1 2 ] , 1957 [ 2 1 1 ] ; Atherton, 1962 [ 2 5 ] ; Becker and Hayes, 1963 [ 4 5 ] ) ,and that it may cost significantly l e s s than subject indexing, jj A major advantage
claimed is responsiveness to user, rather than indexer, interests and view points. zJ
Some of the representative claims with respect to this factor are as follows:1/

See Atherton and Yovich, 1962 [ 2 6 ] , p. 3: "Kessler's method, however, does not
retrieve the references cited by a paper. Instead these references are examined
to determine the 'bonds 1 between papers; e . g . , if two papers share six references,in common, they are said to have a 'coupling strength' of six. By applying eitherof two criteria of coupling, one can 'filter but smaller groups of papers' related
to a given paper. "Salton, 1962 [ 5 2 0 ] , p. IH-8; see also Lesk, 1963 [ 3 5 6 ] .
Atherton, 1962, [ 2 5 ] , p. 3.
4/

See Atherton and Yovich, 1962 [ 2 6 ] , pp. 3-4: "Garfield estimates cost of abstracting and indexing 200, 000 articles in one year to be $3 million. He estimates thecost of a citation index for these same articles (approximately 3 million citations)
to be $300, 000." See also Doyle, 1963, [ 1 6 2 ] , p. 8: "The editing labor, the input
preparation cost, and the automatic processing time are all so small that it's very
likely citation indexing is destined for a great surge of popularity in the immediate
future."5/Committee on Scientific Information, 1963 [ 1 3 5 ] , pp. 55-56: "Because the indexing is based on the author's rather than on an indexer's estimate of what articles
are related to what other articles, citation indexes are particularly responsive tothe u s e r ' s , rather than to the indexer's viewpoint."

30

M

The most feasible scheme for alerting individuals tp what is of interest in theirown field requires an on-going up-to-date citation index. For each narrow fieldof interest of an individual there are, it is believed with good reason, three tofive to ten key items such that:(cl)

If he knew that a new item referred to one of his key items,
the individual would be glad to skim the new item,(c2)

An individual who skimmed all new items referring to oneof his key items would be adequately alerted to the newest
results in his own specialties. f l i /flA research worker who finds one article several years old can relate later
developments by locating all subsequent articles that have referred to it.
Corrections and errata can be brought together by a citation index." .2/"Citation indexing will overcome artificial dividing lines that are drawn in various
abstracting s e r v i c e s . f l $Jtf

It i s believed that citation indexes will be useful. • . i n bringing together relatedmaterials in different fields where the interrelationships are not readily
identifiable from other types of indexes." 4/"Since the end product of a citation indexing is a listing which collects in one
place the bibliographical descendants of a given cited author, bringing these
titles together helps to illuminate for the searcher the extent and nature of
information association patterns employed by other authors who had a similaror related interest to his own. Its development, therefore, serves as an
approach to the user's frame of reference, not the indexer's. 1 1 j>/
The importance of being able to pick up more than the principal subject matterclues is indeed an advantage of citation indexing. Garfield, commenting on the potential
cross-breeding of interests, gives an example of a personal search for more informationon the RCA electronic scanning pencil in which he was led to one of Busa's reports on
machine use in philological analysis and to an article of interest in the field of information theory. f>l Garfield further points out that the cross-breeding can extend across

y
D

1'
±i

Tukey, 1962 [ 6 l l ] , p. 9.
Atherton, 1962 [ 2 5 ] , p. 2. See also Garfield, 1955 [ 2 1 3 ] , p. 1.
/•

Atherton and Yovich, 1962 [ 2 6 ] , p. 3.
Brownson, 1963 [ 8 2 ] , p. 3. See also Garfield, 1957 [ 2 1 1 ] , p. 4.

li
6/Becker and Hayes, 1963 [ 4 5 ] , p. 137.
Garfield, 1954 [ 2 1 0 ] , pp.4-5.
31

1 / and Lipetz suggests that it can break down barrierschanges of terminology with time,-Liwith respect to use of foreign literature, rd
Other claimed advantages relate to the usefulness of the citation index for purposes
other than those of direct literature search. Such other purposes include identificationof significant research by "equating frequency of citation with relative significance of
subject matter lf f (Salton, 1962 [ 5 2 0 ] ) , determinations of the number of references citedin a given field or by journal or publication date (Atherton, 1962 [ 2 5 ] ) , evaluation of therelative importance of various scientific journals (Westbrook, I960 [ 6 3 6 ] ; Kessler, 1961
[ 322]), tracing of trends in the history of ideas or in a particular field of literature(Brownson, 1963 [ 8 2 ] ; Salton, 1962 [520]) 2/ and empirical studies of the frequencies ofself-citation, multiple authorship, and the like (Atherton, 1962 [ 2 5 ] ) .
A number of disadvantages of the citation index are to be noted, however. First i s
the obvious lack of consistency between authors in terms of whether or not they cite theprior literature at all and in terms of the completeness and correctness of the citations
they do make. .1/ Atherton quotes Westbrook as saying:

1/"Science is subject to changing fashions of interest that lead to a distorted
number of published papers in a given subject and an inordinately high levelof citations to any one who reports first on the fashionable subject. The
method will not appraise work performed but not published.
..5/
Ibid, p. 6: "Changes in terminology are to a certain extent overcome through thecitation approach, since the author who makes a reference to a paper that is forty
or fifty years old is making the jump in terminology for u s . " See also Earfield,
1956 [ 2 1 2 ] , p. 11.

2/

Lipetz, 1963, [ 3 6 6 ] , p. 265: "It i s reasoned that availability of a citation index
derived from Soviet physics journals and approachable through familar Americanreferences should stimulate utilization of the Soviet physics journals in the
United States."3/

See also Reisner, 1963 [ 4 9 7 ] , p. 71: "Citation indexes are receiving increasing
attention as bibliographic aids and as sociometric tools. As sociometric tools,
they are being used to explore the flow of information across national boundaries
and from pure to applied fields, to determine the structure of a field, and to
determine the 'value 1 of documents or authors."
4/See, for example, Doyle, 1963 [ 1 6 2 ] , p. 8: "The disadvantages of this kind ofindexing i s , of course, that it depends on authors providing ample and suitablereferences"; Salton, 1962 [ 5 2 0 ] , p.IH-7: "In many c a s e s personal preferences
are evident both as to number and types of papers cited; authors have varying backgrounds, and there may also exist a tendency toward self-citation regardless of
relevancy"; Thompson, 1963 [ 6 0 0 ] , p. II-1: "The difficulties... are largely due tothe extreme variability of format and to the lack of standardization which prevails
in the publication of citations."
5/

Atherton, 1962 [ 2 5 ] , p. 4, citing J. H. Westbrook.

32

An author not cited frequently enough or not cited within a given time period will
not appear in the citation index. Doyle points out that there are "many kinds of documents
we would like to retrieve where it i s not customary to provide citations at all". }J In the
bibliographic coupling method, bot^those papers which make no references to any otherpaper and those papers which do noPfnare at least one reference with some other paperin the system are automatically excluded.
Other disadvantages of the citation indexing technique relate to difficulties of thelack of standard practices in the citing of references and to problems of recognizing
whether one citation is or is not equivalent to another. These are, of course, related to
the normal difficulties arising from non-standardized formats and practices in descriptive
cataloging, in use of journal abbreviations, in transliterations of foreign language titles
and names, and the like, but they are now aggravated by the present prospects for direct
machine processing. As Lipetz points out:
"Author's names may be cited in somewhat different ways, and there is no
simple mechanical procedure for bringing together the different versions.
For example, an author's name may be cited both with and without initials;
it would take a comparison of the additional information on the cited referenceto establish that these authors are the same. Even more difficult are theproblems of mechanically determining that a misspelling has occurred." Jy
Both the disadvantages of incomplete and disproportionate coverage and of failures
to equate equivalent citations are quite readily obvious to the user of a citation index if
he is reasonably familiar with the subject field or document set that is covered. Thus,
the use of the citation index as the exclusive tool for literature search i s subject todefects of both oversight and 'over-cite' which are cumulative and which are often easily
recognizable. Atherton and Yovich emphasize that: "Knowledge of these weaknesses
tends to prevent anyone from trusting the system's ability to retrieve the pertinent
literature." 2J
In general, however, the citation index has not been proposed as an exclusivemeans for literature search and retrieval, but rather as one of a set of tools or as asupplement to other indexes. •*' In this connection, it is of interest to note that a manualtechnique of literature search tested at The Thermophysical Properties Research Center

J7
Doyle, 1963 [ 1 6 2 ] , p. 8.
See Atherton and Yovich, 1962 [ 2 6 ] , p. 39; Marthaler, 1963 [ 3 9 9 ] , p. 23.

II
Lipetz, 1962 [ 3 6 4 ] , p. 262.

±1
Atherton and Yovich, 1962 [ 2 6 ] , p. 39.
See, for example, Tukey 1962 [ 6 l l ] , p. 10: "The citation index, in its retrieval
and pursuit u s e s , i s not something to be used alone. Rather, it i s the tool whose
presence makes all the other tools more effective."33

while not using a citation index as such, makes use of a supplementary citation tracing
technique both to shorten manual search time through abstract journals and to follow up
additional search leads (Lykoudia, et al, 1959 [ 3 8 7 ] ; Cezairliyan, 1962 [ 1 0 7 ] ) . The
technique i s briefly described as follows:"One starts searching the abstracting journal beginning with the most recent
issue and going back through a number of years, ja. Next, the bibliographiesof the papers located in these a years are searched for new references. The
references found in this second step of the search will, in general, cover a
period of years (b - a.). Then one reverts back to searching through the abstracting journal again for another period of * years starting with the year b.
This cyclic procedure of alternate searches through the abstracting journal,
followed by searching the bibliographies of uncovered papers, is repeated until
the total number of desired years of search i s covered." ±J
In a sample search on the thermophysical properties of metals, the results showedthat the cost of the cyclic procedure was only 65% of the cost of conventional manual
search using the abstract journals only.
Recent efforts in the development and use of citation indexes proper include experiments in evaluation at the American Institute of Physics, JJ' .an extensive compilation andprocessing program at the Institute for Scientific Information, 11 and a cooperative program between the Statistical Techniques Research Group of Princeton University and theBell Telephone Laboratories (Tukey, 1962 [ 6 l l ] and [ 6 1 2 ] ) . Reisner has r e ported work on the compilation of a citation index to 30, 000 patent disclosures and its
experimental evaluation in progress at IBM's Thomas J. Watson Research Center (1963[ 4 9 7 ] ) . Goodman i s concerned with a citation index to the literature of new educational
media, especially that on programmed learning and teaching machines (1963 [ 2 3 5 ] ) .
At the Centre d'Etudes Nucleaires de Saclay, a citation index to papers in the fieldof thermonuclear fusion and plasma physics i s being prepared* 2J Lipetz i s carrying on
work in the preparation and evaluation of citation indexes, begun at the Itek Corporation,as an independent worker and consultant to the A. I. P . project. —' Carroll and Summit
report that citation indexing i s under consideration at Lockheed's Missile and Space
Division, (1962 [ 1 0 2 ] ) . Kessler and associates at M . I . T . kl and Salton's group atv
Lykoudis et al, 1959 [ 3 8 7 ] , abstract, p. 351.
Atherton and Yovich, 1962 [ 2 6 ] ; National Science Foundation's CR&O Report
No. 11, p. 12.

11

±1
11
11

Ibid, pp. 27-28
Ibid, p. 76.
Ibid, p. 181.
Ibid, p. 128.

34

the Harvard Computation Laboratory (Salton, 1961 [ 5 1 2 ] , 1962 [ 5 1 3 ] , 1963 [514] and[515]), are concerned with citations as a basis for grouping and categorizing sets ofrelated documents.
Early examples of citation indexes that have been produced include the precedents
in the fields of statistics and information theory listed by Tukey. JL' Tukey also refers toearly experimentation involving manually manipulated card files by J. L. Hodges, J r . ,Charles H. Kraft, and William H. Kruskal. U Goociman (1963 [235]) describes the use ofTermatrex cards showing for each item other items cited by it.
Examples of machine-compiled citation indexes, however, are those of Garfield andSher in the field of genetics (1963 [ 5 4 6 ] ) , Lipetz's experimental index to the citations in
the proceedings of the two United Nations conferences on the peaceful uses of atomic
energy, (1961 [ 3 6 4 ] , I960 [ 3 6 5 ] ) , and the citation index to references listed in the"Short Papers" submitted for the 1963 Annual Meeting of the American Documentation
Institute (Luhn, 1963 [377Q). As of January, 1964, the first five volumes of Science
Citation Index are available from the Institute for Scientific Information. These volumes
are reported to have 2,250, 000 lines of copy representing the computer-compiled citation
trails for 102,000 articles published in 1961. 1'
Preliminary evaluations of the citation indexing principle have, as noted previously,
been carried out in an American Institute of Physics project supported by the National
Science Foundation. One experiment involved the selection of a single paper from theDecember 1, 1961 issue of The Physical Review and the tracing of references and citations
through that journal for the period 1956 tp I960,. A bibliography of 64 papers was produced as a result. This was then evaluated by a nuclear physicist, who found that thetitles alone were an insufficient basis for judging whether or not these papers should all
have been included, and who commented critically that there was no way of knowing if all
the papers really relevant to the subject of the test paper had indeed been found. A
further check by search of the subject index did in fact reveal six pertinent papers which
had been m i s s e d by the citation indexing technique.
A second experiment at the American Institute of Physics involved application of
Kessler's "coupling strength" criteria to 41 of the 64 papers selected in the firstexperiment, the remainder being excluded because they shared no references with anyother paper. The resultant groupings of presumably highly related papers were also
evaluated by a subject matter specialist, who found them relevant to each other but the
selection incomplete. Atherton and Yovich, reporting these A . I . P. experiments, concluded that: "More work will have to be done before the usefulness of citation indexing
can be accurately determined." 2LfyTukey, 1962 [ 6 l l ] , pp. 23-24.

U
Ibid. p. 24.

1'
See news note, Special Libraries, Jan. 1964, p. 58.

±1
Atherton and Yovich, 1962 [ 2 6 ] , p. 22.

35

Kessler himself and his associates have also conducted some experiments incomparative evaluation of indexing aids derived from citation data on the one hand andfrom conventional subject indexing on the other. The basis for evaluation was a total of
334 papers published in The Physical Review in 1958. The study involved detailed
comparison of the ways in which these papers fell into related groups according to the"analytic subject index" used by the journal's editors and according to the method of"bibliographic coupling". The essentials of the latter method are described as follows:"a.
A single item of reference used by two papers i s called one unit of coupling
between them.
"b.
A number of papers constitute a related group Gj^, if each member of thegroup has at least one coupling unit to a given test paper P Q .
"c.
The coupling strength between P Q and any member of G^ is measured by
the number of coupling units (n) between them." 2 /For the 334 papers, 73 categories of the Analytic Subject Index (ASI) had been used.
For the bibliographic coupling method, each of the papers was in turn considered as thetest paper and groups were formed for any of the 333 other papers that shared one ormore citations with it. In general, it was concluded that there was good correlation
between the groupings, of papers achieved by the two methods. It should be noted, however, that 44 papers fell into no groups at all on the basis of the bibliographic coupling
criterion. 2y
Salton and associates at the Harvard Computation Laboratory are also concernedwith the citation indexing principle as a possible basis for grouping similar documents.
They are also concerned with evaluation of results so obtained by comparison with
document groups obtained by subject indexing,means. In the comparative experiments,
data were first compiled for a closed document set of 62 items as to similarities withrespect to both "citedness" and "citingness". The same items were manually indexed
and similarity coefficients between these items were derived from overlappings ofassigned index terms. When the two measures of similarity were compared with eachother and with document associations obtained by random assignments of "citations" and"terms", the conclusions reached were as follows:"The similarity coefficients obtained by comparing overlapping citations for asample document collection with overlapping, manually generated index terms
are much larger than those obtained by assuming a random assignment ofcitations and terms to the documents; relatively large similarity coefficientsare generated for nearly all documents which exhibit at least a minimum
number of citations; little s e e m s to be gained by using citation links of length
greater than two; for early documents, citedness furnishes a better indication
than the amount of citing, and vice versa for recent documents; for documents
which can both cite and be cited, equally good indications seem to be obtainedby comparing citing and cited documents. " 2.1

yKessler, 1963 [ 3 2 0 ] , p. 1, footnote.
Ibid,

p. 5.

If
Salton, 1962 [ 5 2 0 ] , p. IH-42.
36

In the Salton project, tests of the value of citation links for the assignment of index
terms have been made by comparing the citation pattern of an flunknownn document withthose of other documents in the collection to derive a set of five "related 11 documents,
where relatedness is decided on the basis of the magnitude of the similarity coefficientsfor the citation links. Any index term'"'that appears at teasT twice in the set of terms
previously assigned to the five related documents is then assigned to the new item. In
general, approximately 50% of the terms so assigned were also assigned to the same"new11 items by human indexing procedures.
As we have previously noted, however, the advantages of citation indexing are likely
to be most effectively applied when used as part of an array of other tools. Tukey
suggests, in particular, that permutation indexes of titles, as in KWIC systems, would beof great value as "starter" and "re-check" mechanisms for the use of citation indexes..?/Browns on reports:"Consideration is now being given to the possibility of experimenting with a'hybrid1 type of index that would combine permuted titles, authors, and citation
data. Such an index might be more useful than any of the individual types ofindexes issued singly; and, since no human indexing judgment would be involved,
it could be prepared largely by machine and issued rapidly. " zJ
Williams, while at ITEK, proposed a hybrid integrated index combining listings byauthors, corporate authors or author affiliations, keywords-in-context from title* andreferences to works cited by and to works citing an item, and she also developed a sample
format for selected items from several journals in the field of philosophy. 2J
Precisely such a hybrid tool was provided with the Short Papers for the A. D.I.
Annual Meeting 1963, and it was indeed issued rapidly. A brief period of only two or
three weeks elapsed between receipt of many of the manuscripts and the distribution of
two automatically typeset volumes. The second of these volumes contains a KWIC and
an author index to these papers themselves, a bibliography and citation index to all
papers referenced by them, and KWIC and author indexes to the cited papers, allcomputer-compiled within this time period. 2 /1/
Ibid, See also Lesk 1963, [ 3 5 7 ] , p. V-8.
2/
Tukey, 1962, [6ll], p. 12.

II
Brownson, 1963 [ 8 2 ] , p. 4.

±1
T.M.Williams, private communication, dated January 4, 1962.

I!
Luhn, 1963 [376], and [377], pp. 353-382.

37

2. 5

Machine Conversion From One Index Set to AnotherA final possibility in the general area of machine compilation of indexes and machine
use to improve the availability of indexes is as yet in a highly speculative stage. This is
the possibility of converting from one index set to another by machine look-up procedures.
In the Welch Medical Library project, mentioned earlier, use was made of punched card
techniques to convert from one index arrangement to another, A/ but machine recognizable identifiers for both arrangements were explicitly encoded in the material.
In recent studies at Datatrol, however, preliminary investigations have been conducted
looking toward machine lookup of index-term equivalence tables in order to convert, forexample, DDC descriptors to corresponding subject headings used in the AEC vocabulary.
Hammond and Rosenborg (1962 [ 2 5 0 ] and [252]) report on the compilation of a unilateral table of "indexing equivalents 11 between approximately 7,000 DDC descriptors andthose AEC subject headings judged by them to be identical, synonymous, or "usefully"
equivalent, such as one or the other being subsumed by a broader or more generic term.
Findings showed 23. 8% of the terms of the DDC vocabulary presumably identical to thoseof AEC* 38. 1% of lower generic level, 7. 4% of higher generic level, and 10. 9% for which
no useful equivalents could be found. A sample table of indexing equivalents was preparedfor DDC-to-AEC conversion, but not in the opposite direction.
Since, in general, convertibility of indexing vocabularies would be desirable
wherever duplication of cataloging and indexing effort is likely to occur (that i s , where
two or more different documentation organizations receive at least some of the samematerial as inputs to their systems), the results of these preliminary studies are provocative and appear to merit the further study that is being sponsored by an Interagency
Task Group on Vocabulary Study of the Committee on Scientific Information, under theFederal Council for Science and Technology.
There are many substantial difficulties, however. When applied to actual indexingof the same items by the two agencies, it was found that for 277 items indexed by both
AEC and DDC (then AS TLA):"ASTIA used a total of 2, 571 descriptors, and AEC 840 subject headings. . . ofthese, 392, or roughly half of the AEC terms, were either completely or, forall practical purpose, identical. " 2 /Painter (1963 [460]) made further studies of equivalency in her investigations ofduplication and consistency of subject indexing at several Government agencies. For 200
items indexed by both AEC and DDC, she found 20% DDC equivalency, 67% AEC equivalency, and 30% similarity of actual indexing. She concludes, in part:"In considering these solutions and the statistics revealed by the studies it should
be concluded that with a maximum of only 69 percent equivalency, or convertibility,
and a minimum of 28 percent, there is still a large proportion of terms which willuGarfield, 1959 [ 2 2 1 ] , p. 471.
Hammond 1962 [ 2 5 0 ] , p. 4.

38

necessitate some other form of retrieval. This i s the proportion which is involved
with the problem of generics, where a term in one system subsumes two of anotherand v i c e - v e r s a . An additional problem evolve* in attempting to reconcile twodifferent subject concepts, one;the^trtbject hi^aMng^nich usually has a single
access point and one, the Uniterm or descriptor which has multiple access throughcoordination. Thus the practicality of a system made up of many units supplying
information indexed differently, using as a basis for retrieval a table of equivalents,
is questionable. , ! —Moreover, the results of tests of inter-indexer consistency rates within the sameagency were not encouraging. Thus Painter further concludes:r,

Tne study, in combining the results of the equivalency analysis and the consistencyof indexing within each system and an equivalency of only 30 percent within the
broadest system, a table of equivalents is at present of little value in either amanual or a machine system. In order to apply a table of equivalents efficiently,
both a high degree of consistency and a high degree of equivalency is essential. " zJ
She therefore s t r e s s e s that the possibilities for conversion by machine techniquesfrom one indexing set to an equivalent set for another vocabulary are adversely affectedby the generally poor rates of inter-indexer consistency. With reference both to the
Datatrol Studies
and to corroborative findings of her own, she states:f,

The value of equivalency studies and most particularly the table of equivalents
presuppose the consistency of indexing. Convertibility between systems is thus
dependent on the consistency of indexing. Without consistency, the vocabularies
as units are not sound; equivalencies cannot be drawn or effectively used forconvertibility. "Painter, 1963 [ 4 6 0 ] , p. 104.
Ibid, p. ix.
Hammond, 1962 [ 2 5 0 ] ; Hammond and Rosenborg, 1962 [ 2 5 2 ] .
4/Painter, 1963, [ 4 6 0 ] , p. 109. Note that these estimates of inter-indexer consistency may be quite optimistic, as discussed on pp. 157-I60of this report.

39