Merits and Deficiencies 

The principal merit of keyword indexing is the speed with which it can be produced. The production 6f keyword index does not involve costly indexing staff. It requires minimum of intellectual effort compared to those  of other indexing models. The keyword index reflects current terminology in a particular subject field since words used as access points are those used by the author in his title. In as far as an author can be exp6eted  to be an expert in his field, the words used to describe the document seem to be both current and accurate. The cummulation of entries in keyword index is straight-forward. The computer interfiles the entries from a number of batches of input, and prints the cummulative index. Despite their advantages, keyword indexes  suffer  from  some severe limitations. The efficiency of keyword indexing is invariably the question of reliability of expressive titles of documents as most of such indexes are based on titles. If the titles are not meaningful the system becomes ineffective. For example, what conclusion about subject content can you draw from the conclusion about subject content from the title "New rules old games"? Some titles  are  misleading or eye-catching, rather than informative. For example, the subject content of document entitled "Asian Drama" deals  with the economic conditions of Asia, rather than the drama of Asia. Some subjects simply cannot adequately be precisely specified by a short  title. Most of the terms used in science and technology are standardized, but the  situation is  different in  humanities and social sciences. Since no controlled vocabulary is used, keyword indexing appears to be unsatisfactory in respect of control  of synonyrns and  homonyms particularly in the subject areas of the humanities and social sciences. Searching for related subjects, in order to  narrow or broaden a search also presents problems since no recognized hierarchical structure is incorporated in the index. Search of a topic may have to be under several keywords. Search time becomes high in many cases. 

Despite the deficiencies stated above, the keyword index has been quite popular during the last four decades. A number of evaluation studies have indicated that keyword indexes may offer several advantages  over others.  The continued growth of machine-readable databases has shown that the use of keyword indexes works well. The problem of unexpressive titles is solved to a considerable extent by editorial intervention. It is true that KWIC indexes as such will not facilitate comprehensive search. Production of any index taking care of comprehensive search takes time, money and effort. KWIC was never envisaged to provide comprehensive subject index. It is a mechanism of providing quick and specific subject approach to information which Luhn envisaged it to be.