Page 179 - DLIS402_INFORMATION_ANALYSIS_AND_REPACKAGING

Information Analysis and Repackaging

Notes 10.1 Pre-coordinate Indexing Systems

Pre-coordinate indexing systems are conventional systems mostly found in printed indexes. In this
type of system, a document is represented in the index by a heading or headings comprising of a
chain or string of terms. These terms taken together are expected to define the subject content of the
document.
The leading term determines the position of the entry in the catalogue or index, while the other
(qualifying) terms are subordinated to it. Since the coordination of terms in the index description is
decided before any particular request is made, the index is known as pre-coordinate index. Pre-
coordinate indexes are mostly prevalent as printed indexes. For example, the indexes to
abstracting and indexing journals, national bibliographies and subject indexes to library catalogues
apply principles of pre-coordinate indexing in varying measures. Such indexes are compiled both
manually as well as with the help of a computer.
Thus, the pre-coordinate index constitutes a collection of index entries in which concepts from
documents are co-ordinated according to a plan using a linear sequence at the time of the index
headings are prepared. These concepts are then represented either by symbols (when using a scheme
of classification) or words of the indexing language in use. The next step is to synthesize or to put
the components in an order recommended by the rules of the language. This means that the concepts
are pre-coordinated and the index file consisting of a collection of such pre-coordinated concepts
that are available in the library’s collection of documents. These pre-coordinated index when arranged
alphabetically are known as alphabetical subject indexes or alphabetical subject catalogues. When
arranged according to a scheme of classification they are known as classified indexes or classified
catalogues.
Chain Indexing
Chain Indexing or chain procedure is a mechanical method to derive subject index entries or subject
headings from the Class Number of the document. It was developed by Dr. S.R. Ranganathan. He
first mentioned this in his book “Theory of Library Catalogue”.
In Chain Procedure the indexer or cataloguer is supposed to start from where the classifier has left.
No duplication of work is to be done. He/she has to derive subject headings or class index entries
from the digit by digit interpretation of the class number of the document in the reverse direction,
to provide alphabetical approach to the subject of the document.
Ranganathan designed this new method of deriving verbal subject heading in 1934 to provide subject
approach to documents through the alphabetical part of a classified catalogue. This method was
distinctly different from the enumerated subject heading systems like LCSH or SLSH. He discerned
that classification and subject indexing were two sides of the same coin. Classifying a document is
the translation of its specific subject into an artificial language of ordinal numbers which results in
the formation of a class number linking together all he isolate ideas in the form of a chain.
This chain of class numbers is retranslated into its verbal equivalent to formulate a subject heading
that represents the subject contents of the document. The class number itself is the result of subject
analysis of a document into its facet ideas and linked together by a set of indicator digits, particularly
when a classification system like colon Classification is used for the purpose. As this chain is used
for deriving subject entries on the basis of a set of rules and procedures, this new system was called
‘Chain Procedure’. This approach inspired in many other models of subject indexing developed
afterwards, based upon classificatory principles and postulates.
Chain Indexing was originally intended for use with Colon Classification. However, it may be
applied to any scheme of classification whose notation follows hierarchical pattern.

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