PERSPECTIVES: LESSONS LEARNT
University of Linz, Department of Business Information Systems,
Communications Engineering, Freistädterstr. 315, A-4040 Linz
As interactive systems are socio-technical systems, they integrate technical components, namely hard- and software, with a social component, namely the human user. The latter is assumed to be embedded into an organizational setting, such as the work environment ( Stary, 1996). Given this characteristic feature the design as well as the evaluation of interactive systems have to take into account several perspectives, according to Totter et al. ( 1997), and Frese et al. ( 1988): (i) The technical perspective, focusing on interaction modalities, media and styles as well as the (combinations of) software and hardware used in the accomplishment of tasks; (ii) The organizational perspective, concentrating on the global and individual organization of work tasks, (iii) The cognitive perspective, focusing on the individual needs and performance of the end-user.
These perspectives have also been addressed in the field of usability engineering. Usability has been referred to as the quality of a product in use and is defined in the ISO 9241-11 standard ( ISO, 1997) as follows: ,,Usability of a product is the extent to which the product can be used by specified users to achieve specified goals with effectiveness, efficiency, and satisfaction in a specified context of use." This explanation identifies usability as a complex, multidimensional concept, requiring the migration of cognitive components (specified users), the organization of the environment (specified as a set of goals in a specified context of use), such as the workplace, technical features (the product), and their intertwining (interaction).
Hence, for each technique proposed for evaluation it has to be questioned in how far it takes into account different perspectives and their mutual tuning at a user interface. In this paper, a comparative study in that respect with a sample of selected evaluation techniques is presented: Firstly, it has to be analyzed how detailed the procedures guide their users along the process of evaluation, in order to identify categories of elements under evaluation. Secondly, it has to be