We're all familiar with traditional requirements gathering:interview and observe a subset of users, then try to write clear,unambiguous, complete, and testable statements of theirrequirements. Many of us have tried hard to do that and failed. Fromthat, some of us conclude that we should try harder and smarter. Iconclude that the whole idea is broken. You not only can't writeprecise statements in here that represent the worldout there, you can't even come close enough.

In this session, I hope to convince you that my claim is at leastplausible. The next question is: "And then what?" We'llstart to explore ways of putting ourselves in situations where we cancreate better systems without being able to specify requirements.

Topics

• Flaws with the default model.
• At least one technique that doesn't depend on the default model.
• The merits of practice vs. observation.

Since Plato, at least, we've been talking about creating mental models of the world. We usually think of them as like pictures, where everything you can point to in the picture matches something in the world. What if that kind of mental mode is mostly beside the point?

Using exercises, we'll ask two questions: What if the power of a mental model isn't inherent in the model itself, but in the way you explain it to someone else? And what if model-building is powerful when it builds on our expertise, as social animals, at predicting what actions will make someone smile?

This session is related to An Amateur's Guide to Communicating Requirements. It's not necessary to attend both sessions.

Key points:

• You can explain many things using examples and not much more.
• We extrapolate better about specific people than about abstractions.