Design decisions for a user interface

Abstract An approach to user interface design is described in which the prime focus is to stimulate consistency between the mental models developed and the conceptual model of the system. The examination of mental models users formed of relatively simple information retrieval systems, provided the basis for the design of the conceptual model for the information retrieval process. The problems encountered, however, once the semantic level of interface had been specified, are of interest. Which levels of feedback can be distinguished? Which types of feedback should be included at which levels? A framework for the design of the user interface will be proposed and a description of its use in developing an information retrieval system. Four categories of decisions have been identified: decisions concerning (1) interface language, (2) instrumental aspects of interaction, (3) domain-specific strategical aspects of interaction and (4) monitoring facilities (didactic rules, history, user-model). This framework together with the conceptual model, still leaves the designer with a great number of questions and variables. To what extent does the interaction paradigm interfere with or enhance the process of information retrieval? To what extent do the different forms of feedback suffice? The process of design and development will be described, including the pilot study undertaken during this process to test the success of the decisions. Evaluation of the design decisions will include the examination of indications of the quality of users' mental models.