[kqr]

> It forces the team to articulate assumptions and dilineate between in-scope and out-of-scope details.

The more general rule is to force people to put numbers on things.

- Not "will this be expensive?" but "how many dollars do you think this would cost?"

- Not "is this a big project?" but "how many calendar days will this take?"

- Not "will we need a small amount of paint only?" but "how many litres of paint should we buy?"

People very easily come to false agreement over vague terms and goals, but when the numbers come out it's revealed how different their opinions really are, and that's when the useful discussion about assumptions and theory start.