Mastering the Requirements Process, Second Edition

9. Fit Criteria

in which we show how measuring a requirement makes it unambiguous, understandable, and, importantly, testable

Fit, as we use the term here, means a solution completely satisfies the requirement. That is, the solution does exactly what the requirement says it must do or has the property the requirement says it must have, no more and no less. But to test whether the solution fits the requirement, the requirement itself must be measurable. As a simple example, if the requirement calls for a length of rope “of a suitable size,” it is obviously impossible to test any delivered solution. By contrast, if the requirement says the rope shall be “2 centimeters in diameter and 2 meters long,” then it becomes a simple matter to test whether ...