Human Factors for Engineers
This volume introduces readers to the subject of human factors and provides practical and pragmatic advice to assist engineers in designing interactive systems that are safer, more secure and easier to use.
TABLE OF CONTENTS Human Factors for Engineers
Chapter 11: Usability
Martin Maguire
11.1 Introduction
Most computer users will have had experience of poorly designed interactive systems that are difficult to understand or frustrating to use. These may range from a consumer product with many functions and fiddly controls, to a call centre system that is hard for the telephone operator to navigate to obtain the information that a customer requires. System success is therefore very dependent upon the user being able to operate it successfully. If they have difficulties in using the system then they are unlikely to achieve their task goals.
Different terms have been used to describe the quality of a system that enables the user to operate it successfully, such as user friendly , easy to use , intuitive , natural and transparent . A more general term that has been adopted is usability .
11.1.1 Definition of usability
Usability has been defined in different ways. One approach, from the software engineering community, is to define it in terms of system features. The ISO/IEC 9126-1 Software Product Quality Model [1] defines usability as a quality with the attributes of understandability, learnability, operability and attractiveness.
Another approach from the human factors community is to define it in terms of the outcome for the user. Shackel [2], for instance, proposed a definition as the capability in human functional terms to be used easily and effectively by the specified range of users, given specified training and user support, to fulfil the specified range of tasks, within the specified range of environmental scenarios .
This idea that...
Copyright The Institution of Electrical Engineers 2004 under license agreement with Books24x7
