Layered protocols for consumer-equipment interaction: user-interface development for a digital audio recorder

A major issue in user-interface design is how to structure the interaction between the user and the system. A formal model for analysing and designing user-system interaction is expected to be of great help in dealing with this issue and can thus lead to increased usability. In this paper the usefulness of the Layered Protocols formalism is studied. It is studied as an analysis tool as well as a design tool for user-system interaction. Experimental results show that, of two equivalent digital audio recorders, the one designed with the help of the Layered Protocols model is superior to the one that is not: it features higher user task-completion scores and faster user learning.