The proliferation of online public access catalogs (OPACs) requires some systematic rationale for the comparative evaluation of their designs. Considered as an indexing application, the OPAC can be analyzed by three features: the varieties of bibliographic data processed, the kinds of indexes constructed, and the ways in which the indexes are searched. No one configuration applies to every library research project with equal efficacy or likelihood of satisfying queries. However, the rationale proposed can compare and evaluate alternative library computer catalogs in terms of the library's understanding of the relationship between the library's collections and their use.
Chitty, Arthur B., "Indexing for the online catalog" (1987). CUNY Academic Works.