4.1.1 Who should do a walkthrough, and when?

If you're designing a small piece of the interface on your own, you can do your own, informal, "in your head" walkthroughs to monitor the design as you work. Periodically, as larger parts of the interface begin to coalesce, it's useful to get together with a group of people, including other designers and users, and do a walkthrough for a complete task. One thing to keep in mind is that the walkthrough is really a tool for developing the interface, not for validating it. You should go into a walkthrough expecting to find things that can be improved. Because of this, we recommend that group walkthroughs be done by people who are roughly at the same level in the company hierarchy. The presence of high-level managers can turn the evaluation into a show, where the political questions associated with criticizing someone else's work overshadow the need to improve the design.