Images of Usability

The term usability is ubiquitous in human-computer interaction, so much so that it is commonly used without definition. Rather than one established meaning of usability, there are, however, multiple images of usability. While each image provides a partial view, the partiality remains implicit unless confronted with alternative images. This study delineates six images of usability: universal usability, situational usability, perceived usability, hedonic usability, organizational usability, and cultural usability. The different foci of the images provide opportunities for becoming sensitized to manifold aspects of the use of a system and thereby acquiring a genuine understanding of its usability. The six images differ, for example, in the extent to which they include aspects of the outcome of the process of using a system or merely the process of use, whether they involve collaborative use or merely individual use, and in their view of usability as perceived by individuals or shared by groups. Several challenges result from recognizing that usability is a set of images rather than a coherent concept, including a risk of misunderstandings in discussions of usability because participants may assume different images of usability and a need for supplementary methods addressing the collaborative and long-term aspects of usability. Moreover, the images call for extending the scope of practical usability work to include the effects achieved by users during their use of systems for real work.