About the 'Compromised Information Need' and Optimal Interaction as Quality Measure for Search Interfaces

Abstract

Taylor's concept of levels of information need has been cited in over a hundred IR publications since his work was first published. It concerns the phases a searcher goes through, starting with the feeling that information seems missing, to expressing a query to the system that hopefully will provide that information. As every year more IR publications reference Taylor's work, but none of these so much as attempt to formalize the concept they use, it is doubtful that the term is always used with the same connotation. Hence we propose a formal definition of levels of information need, as especially in IR with its formal underpinnings, there is no excuse to leave frequently used terms undefined. We cast Taylor's informally defined levels of information need --- and the transitions between them --- as an evolving dynamical system subsuming two subsystems: the searcher and the search engine. This moves the focus from optimizing the search engine to optimizing the search interface. We define the quality of an interface by how much users need to compromise in order to fill their information need. We show how a theoretical optimum can be calculated that assumes the least compromise from the user. This optimum can be used to establish a base-line for measuring how much a search interface deviates from the ideal, given actual search behavior, and by the same token offers a measure of comparison among competing interfaces.