Write Nonfunctional Fit Criteria (Process Notes 3.8)

The objective of this process is to take a requirement and use the work knowledge to produce a requirement fit criteria for a nonfunctional requirement. The process looks for unambiguous criteria that make it possible to classify any solution to the requirement as either "fits the requirement" or "does not fit the requirement."

The template contains many examples of how to determine requirement measurements.

• Decide what type of requirement you are dealing with; the template will help with this task.

• Is it really a requirement? Requirements are often mistakenly stated as solutions. If this is the case, then you need to ask the stakeholders what the real requirement is, independent from how you might solve it.

• If the requirement is concerned with something that you can touch, see, smell, hear, or taste, then it is easier to find an objective measurement.

• If a noun is not concerned with something that you can touch, see, smell, hear, or taste, then you have a nominalization. A nominalization is created when a verb describing an ongoing process is turned into a noun.

• Suppose you come across this requirement: Maintenance must be reliable. "Maintenance" is a nominalization. You can clarify a nominalization by trying to place bounds on the meaning. Turn the nominalization back into a verb and ask this question: Who is nominalizing about what, and how are they doing it? In the preceding example, ask: Who is maintaining what, and how are they doing it? This technique will help you to identify the real meaning of the requirement; from there you will be able to define an appropriate fit criterion.

• Some requirements are vague nominalizations because no one really knows what they mean or want.