Summary: Putting It All Together

This chapter recaps some of the many things that you have learned about users in terms of their anthropometric, behavioral, cognitive, and social aspects. You have been provided with a lot of information, so we describe a number of different possible ways you can organize it. One way to organize and apply the information is with user models. These models span the range from implicit descriptive models, such as guidelines, through to explicit information processing models, which can be executed to produce behavior and predict performance. Another way is to organize the information based on how to use it. So we finish by looking at one system development process model—the Risk-Driven Incremental Commitment Model—as an example of how you can integrate knowledge about users into the system development life cycle. Failure to consider the users and their tasks during development leads to increased system development risk.