Saturday, April 29, 2017

Chain Indexing

Glossary of Library & Information Science
Glossary of Library & Information Science
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 1938.

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 the alphabetical approach to the subject of the document.

Ranganathan designed this new method of deriving verbal subject heading in 1934 to provide the subject approach to documents through the alphabetical part of a classified catalogue. This method was distinctly different from the enumerated subject heading systems like Library of Congress Subject Headings (LCSH) or Sears List of Subject Headings (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 the 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 afterward, 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 a hierarchical pattern.

Contents

Chain Indexing
  • Steps in Chain Indexing
  • Example of Chain Indexing using Colon Classification
  • Merits of Chain Indexing
  • Demerits of Chain Indexing
  • Conclusion


Steps in Chain Indexing

According to Bhattacharya, there are eleven steps involved in Chain Procedure:
  1. Determination of the specific subject of the document.
  2. Expressive name of the subject
  3. Kernel terms
  4. Analysed name of subject
  5. Transformed  name of subject
  6. Standard terms
  7. Determination of links and construction of chain.
  8. Determination of different kinds of links
  9. Derivation of subject headings
  10. Preparation of cross reference entries
  11. Arrangement.
Determination of specific subject of the document - It is done with the help of the title of the document, its table of contents and by a careful perusal of the text. By analysing the subject contents of a document one arrives at its specific subject.

Expressive name of the subject - Naming the specific subject of the document expressively in the natural language.

Kernel terms - Representation of the name of the specific subject in Kernel terms (fundamental components). It is done by removing all the auxiliary words from the title.

Analyzed name of the subject - Determination of the category of each fundamental component according to a set of postulates and principles formulated for this purpose.

Transformed name of the subject - Transforming of the analysed name of subject by rearranging, if necessary, the fundamental components, according to a few additional postulates and principles formulated for the purpose of governing the syntax.

Standard terms - Standardization of each term, in the transformed name of the subject, in accordance with the standard terms used in the preferred scheme of classification.

Determination of links and construction of chain - Representation of class number in the form of a chain in which each link consists of two parts -- the class number and its translation in natural language. The class number and its translation is joined by “=” sign, and these signs are joined by downward arrows.

Determination of the different kinds of links - Determination of different kinds of links such as Sought Link (SL), False Link (FL), Unsought Link (USL) and Missing Link (ML).

FL : A  link is a false link if it ends with a connecting symbol or relation device, etc.

USL : A link in which a user is not likely to approach a document.

ML : A link in a chain-with-gap, corresponding to the missing isolate in the chain.

SL : A link in which a user is likely to approach a document.

Derivation of subject heading - Derivation of the subject heading from each of the sought links in the chain in a reverse rendering process.

Preparation of cross reference entries - In this step subject reference entry is prepared for specific subject entries.

Arrangement - In this last step all entries are merged and arranged in a single alphabetical sequence.


Example of Chain Indexing using Colon Classification

The document entitled ‘Macbeth’ by William Shakespeare, having class number O111,2J64,M will generate the following chain.

O                          =  Literature (SL)

O1                        =  Indo-European literature (USL)

O11                      =  Teutonic literature (USL)

O111                    =  English literature (SL)

O111,                   =  (FL)

O111,2                 =  English drama (SL)

O111,2J64            =  Shakespeare (SL)

O111,2J64,           =  (FL)

O111,2J64,M        =  Macbeth (SL)

Corresponding to these five sought links, the following subject heading or class index entries will be generated by the above chain:

DRAMA, ENGLISH = O111,2

ENGLISH LITERATURE = O111

LITERATURE = O

MACBETH, SHAKESPEARE (William) (1564) = O111,2J64,M

SHAKESPEARE (William) (1564) = O111,2J64


Merits of Chain Indexing
  1. This procedure, i.e., chain indexing can be applied with ease to any classification scheme whose notational symbols indicate the subordination of each step of division e.g. Colon Classification (CC), Dewey Decimal Classification (DDC), Library of Congress Classification (LCC), etc.
  2. Chain indexing saves the time of the indexer, as he makes use of the class number provided by the classifier, thus, avoiding duplication of work, in analysing the document and the formulation of class number.
  3. Chain indexing provides alternative approaches through reverse rendering to its classified file.
  4. As chain procedure is based on the structure of the classification scheme and on the terminology found in the schedules, its operation is speedy and semi-mechanical.
  5. Chain procedure is economical, as it drops each term after it has been indexed, thus, avoiding the permutation of component terms.
  6. In the case of chain indexing, only one index heading with complete subject formulation is prepared for a specific document. Other entries are prepared by the successive dropping of terms serve a successfully larger number of specific subjects. This provides the facility for generic as well as specific searches.
  7. Chain procedure is amenable to computerization. Programs have been successfully written to generate subject headings both from class numbers and feature headings following the reverse rendering method.
  8. Chain procedure may be used to derive indexes to classification schemes and books. Similarly, it may be used in formulating headings necessary for guide cards on catalogue, stock room guides, shelf guides, etc., in a systematic way.

Demerits of Chain Indexing
  1. It is totally dependent on a scheme of classification, as a result, it tends to suffer demerits related to the scheme of classification automatically.
  2. The entries prepared through chain indexing has only one specific entry, others are all broad entries.
  3. In chain indexing, sometimes a step of a division may go unrepresented, by a further digit of the class number. This creates the problem of the missing chain.
  4. Reverse rendering of terms, while preparing the entries is confusing to the user.

Conclusion

Chain indexing was first used by the Madras University Library in 1936. It has been widely accepted and used by British National Bibliography (BNB) from 1950-1970, LISA is based on Chain Indexing, Indian National Bibliography (INB) has been practicing chain indexing since 1958. Documentation Research & Training Centre (DRTC) has lately found that chain procedure is fully amenable to computerization. Programs have been written to generate subject heading from class numbers following reverse rendering method.


USED FOR
  • Chain Procedure

REFERENCES
  1. Information Access Through The Subject : An Annotated Bibliography / by Salman Haider. - Online : OpenThesis, 2015. (408 pages ; 23 cm.) 
    Information Access Through The Subject

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  • Written 2017-04-29

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Saturday, April 15, 2017

Pre-Coordinate Indexing Systems

Information Access Through The SubjectGlossary of Library & Information Science

PRE-COORDINATE SUBJECT INDEXING SYSTEMS

Nowadays most of the documents deal with complex and compound subjects, each comprising a number of components or concepts. The coordination of these component terms is either done at the input stage or at the output stage. The index in which the coordination of components (index terms) is done at the input stage, is known as a pre-coordinate index.  Coordination of index terms at the input stage means coordination of index terms at the time of preparation of the index by the indexer. In pre-coordinate indexing, a number of selected terms or keywords are coordinated by the indexer and the cards are prepared for display to the users.
          
Examples: Ranganathan’s Chain Indexing, G. Bhattacharya’s POPSI, and Derek Austin’s PRECIS,  COMPASS,  etc.
          
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 catalog 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 a 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 catalogs 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 coordinated 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 indexes when arranged alphabetically are known as alphabetical subject indexes or alphabetical subject catalogs.  When arranged according to a scheme of classification they are known as classified indexes or classified catalogs.

REFERENCES

Information Access Through The Subject : An Annotated Bibliography / by Salman Haider. - Online : OpenThesis, 2015. (408 pages ; 23 cm.)

Annotated bibliography titled Information Access Through The Subject covering Subject Indexing, Subject Cataloging, Classification, Artificial Intelligence, Expert Systems, and Subject Approaches in Bibliographic and Non-Bibliographic Databases etc. 

MLIS Thesis is available and discussed in following places: 
Information Access Through The Subject

The project "annotated bibliography" was worked out as Master of Library & Information Science (MLIS) dissertation in the Department of Library and Information Science, A.M.U, IndiaInformation Access Through The Subject is a very much appreciated work (see Testimonials). It earned the author S. Bashiruddin – P. N. Kaula Gold Medal, Post Graduate Merit Scholarship, First Division, and IInd Position in the MLIS program.


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ARTICLE AUTHOR

ARTICLE HISTORY
  • Written 2017-04-15

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