Principles of Construction Subject Heading:
Some of the main basic principles for construction of subject headings are:
1. Simple and modern heading: We should use simple and modern subject heading and avoid difficult, uncommon and cumbersome phrases.
2. Avoidance of unnecessary subdivision: You have to use the subdivision with a subject only when it is essential and useful and when there are more books in a library or when more books are likely to come covering such subdivision or else. We are avoiding unnecessary subdivision and not make the catalogue and bibliography unnecessarily complicated.
3. Various categories of readers as the focus: We should select such headings that are likely to be used by not one person but by various categories and classes of readers.
4. Unity in terms and avoidance of overlapping words: Different terms may be use by different writer, different times for their titles belonging to a particular subject. The catalogue are in such case, should use a representative unambiguous heading uniting this terms and avoid using different heading which nearly overlap in meaning other heading in the catalogue.
I.e. Biology-574 (class no)
Life Biology-574 (Class no)
5. Terms representing common usage: The heading chosen most represent common usage, or at-least reflect the need knowledge and possible use of a class of readers or it should be use in another library of the same time.
6. Specificity: We should prefer specific to broad heading. The heading should be broader then the content or topic or books (i.e. if the contents are on embryology-574.33). The broader heading Biology may be avoided.
7. Term covering a field and more than one book: Conversely terms covering a particular field and applicable to more than at-least one book are to be used.
8. No more than three subject headings: If a publication cover more than one area, a maximum of three headings may be used. If the subject area tends to be more than three topics, a general heading may be used.
9. Use of the same punctuation, capitalization and form: The same punctuation, spelling, capitalization and form should be employed as given in the list to maintain uniformity.