On indexing, retrieval and the meaning of about

Abstract The primary objective of this paper is to examine the concept of about as it is used in its information retrieval sense when, for example, an indexer judges that a document is (or is not) about some given subject. The problem with about is that it is a very complex notion and we are unable to say precisely what it is we do when we make judgment of aboutness . Since about is at the heart of indexing, how are we to formulate any proper theory of indexing if we cannot explicate precisely the key concept of about? In this paper we look at this concept of about and offer a solution to the problem mentioned; it consists of an operational definition of about which interprets about in terms of search behavior. A second objective of this paper is to show that about is, in fact, not the central concept in a theory of document retrieval. A document retrieval system ought to provide a ranked output (in response to a search query) not according to the degree that they are about the topic sought by the inquiring patron, but rather according to the probability that they will satisfy that person's information need. This paper shows how aboutness is related to probability of satisfaction.