Key Principles and What Designers Think
John D. Gould, Clayton Lewis · 1985
This article is both theoretical and empirical. Theoretically, it describes three principles of system design which we believe must be followed to produce a useful and easy to use computer system. These principles are: early and continual focus on users; empirical measurement of usage; and iterative design whereby the system (simulated, prototype, and real) is modified, tested, modified again, tested again, and the cycle is repeated again and again. This approach is contrasted to other principled design approaches, for example, get it right the first time, reliance on design guidelines. Empirically, the article presents data which show that our design principles are not always intuitive to designers; identifies the arguments which designers often offer for not using these principles-and answers them; and provides an example in which our principles have been used successfully. Any system designed for people to use should be easy to learn (and remember), useful, that is, contain func- tions people really need in their work, and be easy and pleasant to use. This article is written for people who have the responsibility and/or interest in creating com- puter systems (or any other systems) with these charac- teristics. In the first section of this article we briefly mention three principles for system design which we believe can be used to attain these goals. Our principles may seem intuitive, but system designers do not gener- ally recommend them, as results of surveys reported in Section 2 show. The recommendations of actual design- ers suggest that they may sometimes think they are doing what we recommend when in fact they are not. In Section 3 we contrast some of their responses with what we have in mind to provide a fuller and clearer description of our principles. In Section 4 we consider why designers might not actually be using our design