Designing for usability: key principles and what designers think

Reviewer: F. Terry Baker

This article covers three design principles which the authors believe are both important and frequently neglected: (1) Early focus on users and tasks, (2) Empirical measurement, and (3) Iterative design. Gould and Lewis spend more than half of the article discussing why these “common sense” principles are not well understood and why they are undervalued. They then elaborate the principles and explain how they are applied in an initial design phase, followed by an iterative development phase. They complete their discussion by presenting a case study in which they applied these principles to the design of a computer-based audio message system. It is certainly difficult to argue with the importance of these principles. Nevertheless, while the authors go to great lengths to justify them, they do so primarily from the perspective of human factors experts. They, for example, quote Brooks [1] on prototypes, but ignore him on the principle he claims is most important: conceptual integrity. They mention iterative design but do not cite Basili and Turner's seminal article [2] on this topic. While the externally visible aspects of a system are clearly important in satisfying user needs, systems need to possess other attributes to ensure they are buildable and maintainable, and the final design may have to be a compromise as a result. Furthermore, even in the case of externally visible aspects, designers need to ensure that expressed user needs are extrapolated to a complete design which performs in a consistent manner when faced with unexpected inputs. (The reviewer has experience with the system covered in the authors' case study and believes it could be improved in this area.) Thus, while you should read this article to add to your store of knowledge about what needs to be done to satisfy user needs, you should not assume that these principles are the only ones to apply.