Usability in Context: Improving Quality of Use

This paper considers the usability of information systems and IT products in terms of their quality of use for specific users seeking to achieve work goals in particular environments. It describes Usability Context Analysis (UCA), a practical cooperative method for identifying and recording contextual aspects of usability in system development or redesign, and for helping ensure that usability evaluations reflect the context of use and give data with acceptable ecological validity. It draws on experience of applying UCA in commercial settings, working cooperatively with people who have a stake in system development and procurement ‐ including users and managers ‐ to arrive at a clear, shared, documented view of the context of system use. UCA has been developed by the UK National Physical Laboratory (NPL) and HUSAT Research Institute as part of the MUSiC (Measuring Usability of Systems in Context) toolkit. The paper briefly outlines MUSiC methods and tools for quantitative usability evaluation, which complement UCA and support the measurement and improvement of usability. There is still a demand in many parts of Europe, especially in the field of software engineering, for a one-shot ('waterfall') development process for IT systems. Unfortunately, it is rarely possible to prespecify adequately the real-world needs of users and organisations. For users, the outcomes of one-shot development too often fail to deliver hoped for benefits. While the methods described in this paper can be used in enlightened one-shot information system production, the developers of the methods emphasise the value of an iterative, participative prototyping approach, which aims to shape systems to meet user needs. The broad view of usability as quality of use, which underlies the work reported here, stresses the importance of the contexts in which an IT system is used. It avoids the dangers of preoccupation with superficial features of a user interface. Sometimes it is suggested that simply adding a graphical interface, and providing a selection of widgets, will 'solve usability'. As many good designers appreciate, usability is deeper than that. What they may not fully recognise is that designing for usability means providing users with a manner of interaction which meets the needs of those users for achieving their task goals in their own work environments. Even where this is recognised, designers and evaluators may lack access to adequate information about the characteristics of users, tasks and environments. Viewing usability in terms of quality of use opens the way to evaluation which can inform design and redesign, to enable improvement for users in the workplace. It also makes it