Toward a Theory of Indexing-II

The purpose of this paper is to present the elements of a basis for a theory of information storage and retrieval. It is believed that this theory can best be formulated in terms of a general theory of indexing. After stating basic premises and defining essential concepts, the relationship between a theory of indexing and a theory of information storage and retrieval is considered. The similarities between the indexing process and the general communication process are discussed, and indexing is viewed as an order increasing (i.e., entropy decreasing) operation. The concept of a theoretical index is developed and contrasted with real-world indexing systems. The relationship between query formulation, retrieval, and benefit is discussed, and these notions are then related to the human performance variable. It is believed that the ideas presented in this paper provide a useful framework for more detailed investigations into the indexing process.