THE STRATIFIED MODEL OF INFORMATION-RETRIEVAL INTERACTION - EXTENSIONAND APPLICATIONS

User-system interaction is a critical aspect for IR and digital librar ies as well. Thus, a better understanding and modeling of these proces ses is of great importance to efforts aimed at making these systems mo re user responsive. The traditional IR model, with all its strengths, had a serious weakness: it did not depict the rich and varied interact ion processes. Thus, several IR interaction models have been proposed. In 1996 I proposed a stratified model that views the interaction as a dialogue between participants, user and 'computer' (system) through a n interface at a surface level; furthermore, each of the participants are depicted as having different levels or strata. On the user side el ements involve at least these levels: cognitive, affective, and situat ional. On the 'computer' side there are at least engineering, processi ng, and content levels. Interaction is the interplay between various l evels. This general model is now extended to encompass specific proces ses or phenomena that play a crucial role in IR interaction: the notio n of relevance, user modeling, selection of search terms, and feedback types. Examples from a large study of interaction are used to illustr ate these extensions. Suggestions for further research are made.