Code Complete, 2nd Edition

Problem-Definition Prerequisite

The first prerequisite you need to fulfill before beginning construction is a clear statement of the problem that the system is supposed to solve. This is sometimes called "product vision," "vision statement," "mission statement," or "product definition." Here it's called "problem definition." Since this book is about construction, this section doesn't tell you how to write a problem definition; it tells you how to recognize whether one has been written at all and whether the one that's written will form a good foundation for construction.

If the "box" is the boundary of constraints and conditions, then the trick is to find the box…. Don't think outside the box—find the box.

— Andy Hunt Dave Thomas

A problem definition ...