Chapter Introduction | Web Resources | Assignment Comments | Teaching Materials

Textbooks about design and usability testing often make the processes sound straightforward and able to be followed in a step­by­step manner. However, in the real world bringing together all the different aspects of a design is far from straightforward. It is only when you become involved in an actual design project that the challenges and multitude of difficult decisions to be made become apparent. Iterative design often involves carrying out different parts of a project in parallel and under tremendous pressure. The need to deal with different sets of demands and trade­offs (e.g., the need for rigorous testing versus the very limited availability of time and resources) is a major influence on the way a design project is carried out.

The aim of this final chapter is to convey what interaction design is like in the real world by describing how others have dealt with the challenges of an actual de­ sign project. As you will have noticed, we have written primarily about design in Chapters 6-9 and evaluation in Chapters 10-14. This was to enable us to explain the different techniques and processes involved during a design project. It is important to realize that in the real world these two central aspects are closely integrated. You do not do one without the other. In particular, the main reason for doing an evaluation is to make progress on a design.Conversely, whenever you develop a design you need to evaluate it. Whether you are designing a small handheld device or a large air­traffic control system, a design that takes months to produce or one that spans years of effort, the two processes must be carried out together.

The chapter provides glimpses into the design and evaluation process for quite different types of interactive systems. The first two case studies discuss the design of mobile communicators for different groups of users, showing how the design is­ sues differ for each group. The third case study examines the redesign of a large interactive voice response system. In the original design, the focus was on developing a system where the programmers used themselves as models of the users. Further­ more, the programmers were more concerned with developing elegant programs than with users' needs for easy interaction. As you will see, this caused a mismatch between their design and how users tried to find information. This is a common predicament and interaction designers are often brought in to fix already badly designed systems.

The main aims of this chapter are to: