Humane Interface, The: New Directions for Designing Interactive Systems

4-2. GOMS Keystroke-Level Model

The aim of exact science is to reduce the problems of nature to the determination of quantities by operations with numbers.

—James Clerk Maxwell, On Faraday's Lines of Force (1856)

I will introduce only the simplest—yet nonetheless valuable—aspect of the GOMS method: the keystroke-level model. We designers who know GOMS rarely use a detailed and formal analysis of an interface design, but that is due, in part, to our having absorbed the fundamentals of GOMS and of other quantitative methods such that our designs inherently incorporate GOMS teachings. We do bring formal analysis into play when choosing between two approaches to interface design in which small differences in speed can have significant economic or ...