(PREserved Context Indexing
PREserved Context Indexing System.
Developed by Derek Austin in the early 1970s for
subject indexing for the British National Bibliography.
Subsequently developed by him, with the assistance
of Mary Dykstra, into an adaptable method of linking
both the semantics and syntax of indexing terms.
Goal was to represent meaning without “disturbing
the user‟s immediate understanding.”
It is a development of Chain Indexing.
PRECIS was replaced by COMPASS in 1990.
The British Library compiled an internal thesaurus
for PRECIS-indexing of the British National
Bibliography from 1950-1987.
The PRECIS thesaurus has, never been available
Two most important factors worked for
the development of PRECIS:
Idea of replacing chain indexing technique of
The decision of the British Library to generate
computer produced BNB with all the indexes
in view of launching the UKMARC project
Concept of PRECIS
A term is a verbal representation of a concept. It
may consist of one or more words.
An ordered sequence of component
terms, excluding articles
connectives, prepositions, etc., proceded by role
operators is called a string. The string represents the
subject of the document.
The Operators are the code symbols
which show the function of the component term and
fix its position in the strings. These role operators are
meant for the guidance of the indexers only and do
not appear in the index entry.
Major task involved in indexing
according to PRECIS,
Analyzing the document concerned and identifying key
Organizing the concepts into a subject statement based
on the principle of context dependency.
Assigning codes which signify the syntactical function
of each term.
Deciding which terms should be the access points and
which terms would be in other positions in the index
entries ,and assigning further codes to achieve these
Adding further prepositions ,auxiliaries or phrases
which would result in clarity and expressiveness of the
resulting index entries.
Enviornment of core
Key system; Object of transitive action;
agent of intransitive action
Action; effect of action
Performer of transitive action ;intake; factor
View point –as-form
Selected instance,eg-study region ,sample
Form of document; target user
Standard coordinate concept
Member of quesi-group
Special class of action
1st concept in coordinate
2nd/subsequent concept in
In PRECIS entries are generated in a two-line
The first line, consisting of two lines-the lead and
the qualifier. Other line consist of Display.
The lead is the user‟s access point to the index;
the qualifier contains the terms that set the lead
into its wider context;and the display contains the
terms that rely upon the heading for the context.
Standard format :
„Lead‟ position serves as the users‟ approach
term, by which a user may search the index.
Qualifier: It represent the term or set of terms which
qualifies the lead term to bring it into its proper
context.It provides wider context to the lead term.
Display: It is the remaining part of the string which
helps to preserve the context.
All the terms in the string are prepared using the
PRECIS table, are then rotated according to a
The structure adopted for the process is as
The approach term is placed one by
one in the lead term section, with the succeeding
terms (if any) as qualifier and the preceding terms
(if any) in the display section, displaying the
context of the terms.
Computerization of libraries in India
Predicate Transformation Format
The Predicate Transformation Format is
used when the teem representing an agent (3)
appears as a lead term prefixed by one of the
operators 2 or s or t. When such a situation
arises, 2 or s or t is shifted to Display position from
the Qualifier position.
3. Inverted Format
PRECIS makes the use of inverted format
when any term is provided the role operators (4), (5)
or (6) and these terms appear as Lead terms. When it
happens so, the dependant elements are presented
in italics (or underlined if handwritten) after a hyphen
and the terms in the Qualifier position are printed in
Aspects of PRECIS Indexing:
Context is preserved: The entire indexing
statement appears at each lead term;
The permuted entries read naturally, which is
achieved by the prescribed order of the role
The terms are linked to a machine-held thesaurus
(not described in this presentation) thereby
providing possible see’s and see also’s ;
According to Austin, PRECIS can be adapted to
The indexer determines meaning and codes the
roles and lead terms, but the computer takes care
of the permutations.
Essential Features of PRECIS
The system derives headings that are coextensive with the subject at all access points.
It is not bound to any classification scheme .
The terms are context dependent in nature,
which enables the users to identify the entries
The entries are generated automatically by the
computer references between semantically
It also provides adequate arrangement of
references between semantically related terms.
It is a flexible system, as it is able to
incorporate newly emerging terms accordingly.
It has introduced the PRECIS table which puts
forth a set pattern for the preparation of entries,
thus bringing about consistency in work.
Indexing with PRECIS requires a good
knowledge of grammar;
The bottleneck comes at the first step: articulating
the title-like phrase.
It‟s not clear how the terms provided by the
indexer are harmonized with the thesaurus to
produce “consensual meaning.”
PRECIS was first adopted by BNB, later on
a number of agencies went to accept the system.
Among the other national bibliographies that
adopted PRECIS are Australia, Malaysia and
South Africa. Besides these, a number of libraries
in Britain are practicing it. A number of pilot
projects are also practicing and for creating
indexes to statistical, public and other records.
Chowdhury , G.G(2010).Introduction to
Modern Information Retrieval(2nd ed.)New
delhi. Facet publication.
Austin, Derek. PRECIS: A Manual of Concept
Analysis and Subject Indexing. 2nd ed.
London: British Library Bibliographic Services