Action-effect rules: a technique for evaluating an informal specification against principles

Abstract

The technique described here involves generating a user-centred specification of the system in terms of ‘action-effect rules’. This specification is then examined for violations of principles. In this paper we consider hard to reverse effects and ambiguous displays. Additional principles which might be used are also discussed. The technique is demonstrated with an example which also shows how it can be incorporated, with user testing, into an iterative design methodology. Action-effect rules are easier to generate than many of the alternative schemes. They can be extracted from the functional specification a designer will have to produce anyway. Specifying the user interface of a system with action-effect rules encourages the designer to think about the problems of the user from the earliest stages of design.