The support of effective interaction of the user with the other components of the system is a central problem for information retrieval. In this paper, we present a theory of such interactions taking place within a space of information-seeking strategies, and discuss how such a concept can be used to design for effective interaction. In particular, we propose a model of information retrieval system design based on the ideas of: a multi-dimensional space of information-seeking strategies; dialogue structures for information seeking; cases of specific information-seeking dialogues; and, scripts as distinguished prototypical cases. We demonstrate the use of this model by discussing in some detail the MERIT system, a prototype information retrieval system which incorporates these design principles.

We present an analysis of information retrieval as an information-seeking activity, supporting people's interactions with text. This analysis suggests that some assumptions underlying the standard model of information retrieval are inappropriate, and we suggest alternative assumptions and discuss their implications for information retrieval system design. It is proposed that information retrieval is most properly considered as information-seeking behavior, that the central process of information retrieval is user interaction with text, and that the user is the central component of the information retrieval system. Possible ways to incorporate this view in the design of information retrieval systems are discussed.

Familiar evaluation methodologies for information retrieval (IR) are not well suited to the task of comparing systems in many real settings. These systems and evaluation methods must support contextual, interactive retrieval over changing, heterogeneous data collections, including private and confidential information. We have

The paper highlights the ever increasing complexity in the evaluation of IR systems which has arisen over the last decade. Relevance, cognition, user behaviour, interaction and a changing view of the boundaries of the system are considered to be contributory factors. Issues such as laboratory versus operational systems, black-box versus diagnostic experiments, and qualitative and quantitative methods, are discussed and supported by examples drawn from three groups of evaluative experiments: weighted searching on a front end system, information seeking behaviour and the use of OPACs, and the OKAPI experimental retrieval system. The volume edited by Sparck Jones and published in 1981, Information Retrieval Experiment, remains the one substantial work on the evaluation of IR systems. The first chapter, by one of the present authors (Robertson, 1981), ended with the thought that the succeeding twenty years might see as much change in this field as the previous twenty: If, in 2001, this entire chapter is obsolete, so much the better! As we are now half way through that period, an overview is appropriate. It is the contention of the present paper that the field has changed substantially in ten years. 1