The main aims of this chapter are to:
As products evolve from initial ideas through conceptual design and prototypes, iterative cycles of design and evaluation help to ensure that they meet users' needs. However, deciding when and how to evaluate a product requires careful consideration and may be different for different kinds of products. This can be challenging given the rapid development of a wide variety of mobile and distributed systems.
The design process starts with the designers working to develop a product that meets users' requirements, but understanding requirements tends to happen by a process of negotiation between designers and users over a period of time. As designers understand users' needs better, their designs reflect this understanding. Similarly, as users see and experience design ideas, they are able to give better feedback that enables the designers to improve their designs. The process is cyclical, with evaluation facilitating understanding between designers and users.
Evaluation is driven by questions about how well the design or particular aspects of it satisfy requirements and offer appropriate user experiences. Some of these questions provide high-level goals to guide the evaluation. For example, does ...