Successful human factors evaluation of interactive computer systems has tended to relyheavily on the experience of the practitioner, who has had little explicit support on which to draw. This paper concerns support for evaluation in the form of a framework for describing and guiding the general activity. The paper starts with a critique of current approaches to evaluation, and particularly of evaluation within the 'design for usability' approach. Following a definition of evaluation, a framework is proposed that attempts to clarify what can be done towardswhich goals and how it can be done. This highlights and discusses notions of system performance, of assessment statements, and of assessment methods. The paper concludes with a discussion of the implications of the framework for evaluation practice.

No abstract

No abstract