A-posteriori indexing, classification and retrieval of textual data

This paper reports on a series of programs that have been developed to process data-bases, consisting of textual items, and to index and arrange (classify) the data items in accordance with an automatically generated classification system. The programs produce directories and a classification-number ordered data-base on microfilm, where it may be searched using a microfilm reader, or on magnetic tape for input to an on-line computer system for search and retrieval.

In the automatic indexing, candidate index words or phrases are selected automatically and the user can reject unsuitable candidate words, en masse, based on various listings prepared by the computer.

The automatic classification of text items in conjunction with the indexing produces a number of useful features. First, it allows the grouping of “like” items on a print-out, on microfilm or in computer storage. This organization of the items is useful for searching and understanding of the content of the data-base. Searches by conjunction of index terms are simplified and can be performed manually (or automatically) using the directories that are produced.

Automatic processing of raw text data, and requiring little user work make the system attractive where low cost is imperative, such as in private or specialised data-bases.