Free Blogger Templates

POPSI (Postulate-Based Permuted Subject Indexing)

POPSI (Postulate-Based Permuted Subject Indexing)


The inherent weakness of chain indexing has been its dependence on a scheme of classification. Another weakness was its disappearing chain. In view of this situation, the information scientists at the Documentation Research and Training Centre (DRTC), Banglore, directed themselves from these limitations; the Postulate Based Permuted Subject Indexing (POPSI) is the results of these efforts. It was developed by Ganesh Bhattacharya.

POPSI does not depend on the Class Number but is based on Ranganathan’s postulates and principles of general theory of classification.

POPSI  is specifically based on:

(a) a set of postulated Elementary Categories (ECs) of the elements fit to form component of subject proposition.

Elementary Categories are:

Discipline (D) - It covers conventional field of study, e.g. Chemistry, Physics, etc.,

Entity (E) - e.g. Plant, Lens, Eye, Book, etc.,

Action (A) - e.g. Treatment, Migration, etc; and

Property (P) - It includes ideas denoting the concept of ‘attribute’ – qualitative or quantitative. e.g. Power, Capacity, Property, etc.

(b) a set of rules of syntax with reference to ECs

The Syntax is based on Ranganathan’s general theory of classification.

(c) a set of indicator digits or notations to denote the ECs and their subdivisions. It is got by POPSI table as given below:


0 = Form modifier

1 = General treatment

2 = Phase relation

2.1 = general

2.2 = bias

2.3 = comparison

2.4 = similarity

2.5 = difference

2.6 = application

2.7 = influence

3 = Time modifier

4 = Entity modifier

5 = Place modifier

6 = Entry

7 = Discipline

(d) a vocabulary control device designated as ‘Classaurus’.


  • Format
  • Steps in POPSI (with Example)
  • Conclusion


If A,B,C,D are subject headings (using each of the sought terms) then it will generate the following subject entries.





The above format is exactly like KWOC  index, in which the user is required to read the entire chain every time to get the correct context.

Steps in POPSI (with Example)

The index entries according to this system are generated in a systematic manner with the help of following steps of operation.
  1. Analysis
  2. Formalisation
  3. Modulation
  4. Standardisation
  5. Preparation of EOC
  6. Decision about TA
  7. Preparation of EAC
  8. Alphabetisation
Let us examine these stages with the help of a sample title, ‘Chemical treatment of tuberculosis of lungs’.


Subject indicative expression, the starting point of index generation, may be the title of a paper, a book or any other document. According to the first stage of operation, the expression is analysed to identify the facets in terms of concepts and modifiers. Analysis of the above mentioned example will lead to the following:
D       -        Medicine
E       -        Lungs
A       -        Chemical Treatment
P       -        Tuberculosis


In the stage of formalisation the sequence of components derived by analysis has to be decided. It involves the arrangement of component terms according to the principles of sequence of components indicating the status of each component term. Applying this principle, the components are sequenced in the following manner to obtain the basic chain:
Medicine (D), Lungs (E), Tuberculosis (P of E), Chemical treatment (A on P)


Each of the component terms in the analysed and formalised subject headings is added some terms (if necessary) to make their understanding more clear. The above chain after modulation will be:
Medicine (D), Man. Respiratory System. Lungs (E), Disease. Tuberculosis (P of E), Chemical treatment (A on P)


It is concerned with semantics. It helps in the decision of standard terms for synonyms and the terms for reference generation. It is done vocabulary control. In step 3 and 4, classaurus has been suggested to be used. The above chain after this step will be:
Medicine (D), Man. Respiratory System. Lungs (E), Disease. Tuberculosis (P of E), Chemotherapy (=Chemical treatment) (A on P)

Preparation of the EOC (Entry for Organising Classification)

It consists of preparing the entry for generating organising classification by inserting appropriate notations from the POPSI table. The above chain after this step will take the following shape.
7 Medicine, 6 Man. Respiratory System. Lungs, 6.2 Disease. Tuberculosis, 6.2.1 Chemotherapy (=Chemical treatment)

Decision about TA (terms of approach)

This step is concerned with the decision regarding terms of approach for generating successive index entries and references.

In this step ‘Lungs’, ‘Tuberculosis’ and ‘Chemotherapy’ are selected as terms of approach and a cross reference entry is decided to be made for ‘Chemotherapy’.

Preparation of EAC (Entries for Associative Classification)

This step consists of the preparation of entries under each approach terms and references. This step will result in the following entries.

          7 Medicine, 6 Man. Respiratory  System. Lungs,
          6.2 Disease. Tuberculosis, 6.2.1 Chemotherapy

          7 Medicine, 6 Man. Respiratory  System. Lungs,
          6.2 Disease. Tuberculosis, 6.2.1 Chemotherapy

          7 Medicine, 6 Man. Respiratory  System. Lungs,
          6.2 Disease. Tuberculosis, 6.2.1 Chemotherapy

Chemical treatment
          See Chemotherapy


In this step, all the index entries including references are arranged in a word by word sequence

(i) Chemical treatment
           See Chemotherapy

(ii) Chemotherapy
            7 Medicine…       …

(iv) Lungs
            7 Medicine  …       …

(iv) Tuberculosis
            7 Medicine  …       …


POPSI is certainly an extension of Chain Indexing,  though they differ from each other. POPSI has successfully solved the problem of disappearing chain which was a major criticism against chain indexing. POPSI made the indexing system free from classification scheme because this system is based on the general theory of classification and is not tagged with any classification scheme.

  • Postulate-Based Permuted Subject Indexing

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



  • Salman Haider - Librarian Cataloger Author Blogger


  • Last Updated: 2019-07-04
  • Written 2017-05-04

  • Help us improve this article! Contact us with your feedback. You can use the comments section below, or reach us on social media.