Depth classification

Depth Classification

1.0 Meaning of depth classification:

To Ranganathan, depth-classification is ‘a scheme of classification fitted to reach co-extensiveness and expressiveness in the classification of micro thoughts having many rounds and levels of facets and isolates of high orders in any or all of them (Ranganathan, 1957). A schedule of depth classification scheme can be developed by extending a class in general classification scheme.

1.1 Need of depth-classification:

All social institutions for their successful survival have to respond positively to the various social pressures. The library is a social institution. As a social institution, it is pressurized to develop new techniques to organize the ever-growing, diverse universe of subjects. Depth Classification

The human race has a great passion for specialization. Increasing specialization ultimately results in the creation of documents dealing with micro thoughts. For the systematic organization of documents dealing with micro thoughts depth classification schemes are needed. In another word it is a scheme that are needed to provide the expressive, individualizing, unique class number to any micro thought within any number of facets and phases.

Ranganathan explains the need of this classification in the context of research saying that ‘depth classification schemes of micro subjects functions, as a link in the chain of communication needed to prevent the reversion of relay-research into research by isolated individuals (Ranganathan, 1989h).

This schemes are also needed to bring together all aspects of a subject. Need and importance of this classification are further explained by Bhattacharyya (1969).

The need for depth classification schemes can be more precisely proclaimed as-

1. Most general classification schemes do not give adequate details for precise representation of the highly complex subjects in papers and reports that documentation must handle today.

2. Broad classification schemes do not have an optimum helpful sequence.

3. The highly specialized subjects catalogued today are compound, they can be accurately designated by subject headings which combine two or more terms. Each term may be used in a great variety of combinations. So it is necessary to have complete flexibility in forming combinations. Such flexibility is provided by depth classification.

1.1.1 Depth classification and documentation activities: The efficiency of any information storage and retrieval system depends upon two things.

(i) Selecting standard terms to representing micro subjects.

(ii) Creating compound headings by arranging the component terms in a helpful order.

Any general, broad classification scheme cannot truly serve both the self-arrangement and documentation. The depth classification schemes fulfill both these requirements, for it lists micro subjects and provides rules for synthesizing the various terms representing the subject. Further a term- in a compound phrase may form part of many combinations and it is only the depth classification’s faceted nature, which provides complete flexibility in coordination of terms. The depth classification schemes employ more means to minimise the schedule size.

Such being the usefulness of depth classification, Ranganathan estimated the need for about 5000 depth classification schedules (Ranganathan, 1964c). Responding to this need, up till now about 100 depth classification schedules covering about 120 basic subjects have been constructed in India (Gopinath, 1966).

Depth classification schedules, so far developed, mostly cover engineering and technology subject field (Gopinath, 1966). The social sciences and interdisciplinary subjects have not been paid much attention to. This research aims to fill up this gap by constructing a depth classification schedule of LIS, an interdisciplinary subject.

1.2 Approaches/methods used in the construction of this classification schemes:

There are two basic approaches following which, a depth classification scheme/schedule can be constructed. These approaches are:

(i) The speculative approach: This approach is also recognized as a priori approach. According to this approach, the classification schedule is constructed on the basis of conjecture.

(ii) Pragmatic approach: This approach is also called as literary warrant approach. This approach recommends that the classification schedule should be constructed by following the literary warrant.

(iii) The blending approach: Use of only one of the approach mentioned above may throw the classification schedule out of focus. To avoid this Ranganathan has recommended the use of `blending method’ i.e. the combination of both the above methods (Ranganathan, 1964).

Milstead (1984) provides a comparative account of the a priori and pragmatic approach. She writes that ‘most classifications construct pigeonholes, which are performed without reference to the subject of a particular document.¬†

Therefore documents are put into the pigeonholes “close in size to the subject”. Co-extensiveness is based on the subject of individual documents while pigeonholing is based on the structure of the system.

Explanation of each step involved in the construction of depth classification scheme is provided by Ranganathan in his article published in 1964 (Ranganathan, 1964a). This is a very basic article on the subject. Neelameghan (1969) has also explained with an example, the methodology to be followed in the construction of depth classification schemes.

Designing of a depth classification scheme by applying the pragmatic approach is explained by Neelameghan and Gopinath (1965) through a case study of the subject ‘Diesel Engine Production Engineering’.

Neelameghan and Gopinath (1965a) present an investigative account of design methodology for the depth classification scheme. They also explain the methodology of making the design work amenable to the scientific method and making the work of classificationist and of the classifier more productive.

M. A. Gopinath has published a manual giving step by step instructions for the construction of depth classification scheme (Gopinath, 1986a).

B. C. Vickery has prepared a comprehensive manual providing guidance for the construction of faceted classification (Vickery, 1960).

1.3 Common isolates and the depth classification schemes:

This classification scheme so far constructed on the basis of CC, basically give isolates of Personality facet. Few isolates of Matter [MP] and Energy [E] facet are also given. Most of the isolates of [MP] and [E] facet are believed to be common to many main classes. The methodology of searching common [MP] isolates is described by Ranganathan (1960). The seventh edition of CC provides a list of common matter property and common energy isolates (Ranganathan, 1987d).

1.4 Lengthy class numbers of depth classification schemes- a justification:

For representing micro subjects multiple terms are needed. For representing more components of a subject in a class number more notational symbols are needed.

Depth classification schemes endeavor to facilitate individualization of specialized subjects. This is done by representing every component of a compound subject and as a result, the class number becomes lengthy. By virtue of more digits and connecting symbols, the class number becomes cumbersome too.

Thus, the choice is between non-coextensive, short, easy class number provided by the general classification scheme and coextensive, lengthy class number provided by the depth classification scheme. The excellence in librarianship in general and information storage and retrieval, in particular, forces to favor the later of the aforesaid alternatives.

1.5 Depth classification – dual use: To provide options and varieties is the ‘command’ of ‘The great creator’; [That is why probably, the human beings are provided with two hands, two eyes etc. instead of one] and to choose the right option is the intelligence and judgement of the ‘created’. Similarly, this classification schemes offer class numbers for specialized topics as well as for broad subjects. It is the privilege of the information organizer to choose the option, expedient to his purpose.

2.1 Rational for selecting CC as a model for designing the present depth classifications schedule:

Species of classification schemes available for selecting as a basis for designing a depth classification schedule are:

1. Purely enumerative

2. Almost enumerative

3. Almost faceted

4. Rigidly faceted

5. Freely faceted

Amongst these species of classification schemes, only the freely faceted classification scheme offers freedom in the sequence and number of facets. So only the freely faceted classification schemes can be of use in the depth classification of newly emerging micro subjects. A more detailed explanation for using a freely faceted species for designing a depth classification schedule is provided by Ranganathan (1966).

A freely faceted scheme analyzes a subject and arranges the facets available in it in a helpful sequence. It also provides rules for number building by synthesizing appropriate facets. This is why the faceted schemes are also called analytico-synthetic classification schemes. The seventh edition of CC belongs to the freely faceted species of classification and so it is chosen as a model for designing the present depth classification schedule. In addition to this justification, the following two reasons substantiate the decision favoring CC as a model for designing the depth classification schedule.

(i) CC is based on a sound theoretical foundation. It’s normative principles, canons, postulates, principles of facet sequence and the various devices guide objectively in the design of depth classification (Ranganathan, 1989i).

(ii) Notational qualities: CC uses mixed notation consisting of Roman alphabets, both upper and lower case, Indo-Arabic numerals, various punctuation marks, and mathematical symbols. This extensive base of the notational system provides tremendous scope for the interpolation and extrapolation through various devices. The large base of this notational system also helps to have shorter class numbers.

2.2 Notational system:

Ranganathan provides a descriptive account of a notational system useful for designing a depth classifications scheme. He explains it with a case study of a classification schedule of ‘Push bicycle’ (Ranganathan, 1972). Neelameghan and Sangameswaran (1966) explain the use of array division with packet notation.¬†

Reference Article:

  • Kumbhar, R. M. (2003). Contruction of vocabulary control tool thesaurus for library and information science. retrieved from:
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