Chapter 1 LANGUAGE MODELLING AND RELEVANCE Karen

1. Introduction This paper addresses three questions about the Language Modelling (LM) approach to information retrieval. These questions are about LM and relevance. They arise because relevance has always been taken as fundamental to information retrieval (see, e.g. Saracevic, 1975, or Mizzaro, 1997). Thus from the standpoint of retrieval theory, the presumption has been that as relevance is the key notion in retrieval (for how could it not be?), this should be explicitly recognised in any formal model of retrieval. The Probabilistic Model (PM) of retrieval does this very clearly.