SOME LESSONS FROM AN EXERCISE IN SPECIFICATION USING FOLEY AND VAN DAM'S INTERFACE DOCUMENTATION METHOD
David Mark Frohlich, Paul Luff · ACM SIGCHI Bulletin · 1988
Formulating precise descriptions of human-computer interactions is a prerequisite for the principled design, implementation and evaluation of interactive systems. This poster reports an exercise in interaction specification using Foley and Van Dam's (1982) multi-layered method of documenting the design of a user-computer interface. The specification was used to communicate the intended behaviour of a Forms Helper system from a design team to an implementation team. The ease with which the interaction could be represented at each of Foley and Van Dam's four levels of abstraction is discussed, and recommendations are made for improving the method in places where its guidance was unclear or inadequate. The value of the specification to the implementors of the system is examined prior to a discussion of the potential role of such specifications in the design and development cycle.The main conclusions of the exercise are as follows. The power of the method for expressing system behaviour was lacking at the semantic and syntactic levels, and checking the specification for consistency was difficult between levels. However, with regard to the understandability of the specification our impression is that the multi-layered descriptions worked well as a vehicle for communication. In general, the specification was precise enough to allow the complete Forms Helper system to be implemented from it. The fact that it could be produced from a description of the interaction alone indicates that for certain systems at least, the Foley and Van Dam method of interface documentation can serve as a means of interactive system specification.