Using video disc storage technology and alternative input devices, system designers can give end-users of interactive systems more flexible access to information. But improving accessibility does not automatically improve usability of the information provided by such systems. To insure that users not only understand but make efficient use of information, human factors engineers need to develop new styles of structuring the information that must eventually be presented to end-users. New types of user-interface functions must be designed for giving end-users better control over the means by which they can access and use the information presented by these systems. This paper summarizes the experience gained in improving the user-interface to an interactive video disc system, installed as a network of touch-sensitive terminals in a large public area. Questions are proposed to aid the human performance engineer in defining functional requirements, and methods are outlined for structuring the information content. Finally, step-by-step guidelines are offered for conducting structured walkthroughs of the user-interface design, and matrix formats are presented for documenting the results of these procedures.
