In the early stages this may be only a sketch of a few screens. Within weeks it may contain rendered images of a number of screens with buttons to allow the user to click through realistic scenarios, for demos and customer feedback. Later in the process, the prototype may look and feel like the real product, with sufficient realism for effective usability testing. At all times, the prototype must reflect a consensus view of the product, so that the development and marketing teams can move forward with a common vision. Building such prototypes is a distraction for the development team, who need to produce robust, scaleable software.
Prototypes are fragile, throw- away code.
Product prototypes are produced as an integral part of our usability design process, ranging from quick appearance models to high-fidelity prototypes which look and feel like the finished product and automatically log user actions for analysis. Any user-centered design process must include testing with real users. It is bad practice for the designer or implementer to conduct such tests. I have a number of excellent associates I can draw on for such testing, and would include their work in any proposal for clients who do not have this skill in-house. Design for Human Reliability Jon Stuart, who recently joined Positive Interaction as an associate, has extensive experience in the design of systems to minimize the likelihood and impact of human error.