Guidelines. An approach in the evaluation of human-computer interfaces

Many approaches to evaluate user interface after the product design is completed (summative evaluation) have been formally proposed. However, the use of project guidelines during this phase is not explicitly mentioned in the literature. Much has been written, on the other hand, about the effective use of guidelines as a design strategy, with examples of their use both for the specification and design phases of the interface project (formative evaluation). This paper presents the results of a case study where guidelines were used during the evaluation and re-design of a human-computer interface. It describes the analysis and optimisation of the interactive mechanisms of an image processing system, and concentrates on the following aspects of the user interface: visual and semantic consistency, use of colour, message presentation and continuity of the communication process. The paper concludes with the discussion of this evaluation approach based upon a comparison of the user satisfaction levels before and after the system critical analysis and subsequent modifications