In information retrieval, computers were used for preparation on in-house indexes i.e. within the library and also for production of indexes for major abstracting journals. Index consists of a series of terms arranged in alphabetical order. There are different types of computer produced indexes:
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KWIC (Key Word In Context) : In a KWIC type index, an entry for a document is made under each keyword in the title of the document. The computer must be told how to derive the keywords, these being the words which characterize the subject.
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KWOC (Key word Out of Context) : In this Index, the keyword remains in the title. This method greatly increases the size of the index but if there are many entries under one term, it sub-divides the entries. It is used by many special libraries for indexing reports, journals, patents etc.
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