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Once the question has been determined, the next step is to agree on the form of an acceptable answer. A clear agreement on the form of an acceptable answer helps ensure that both parties have the same question in mind.

Thinking about the form of an acceptable answer may, in fact, lead to refining the question, especially if you play “devil's advocate” and look for “silly” answers. If “silly” answers are not precluded by the form of the question, then the question needs to be refined.

The question “What is the effectiveness of this heat exchanger at its design conditions?” needs only a single number for an answer: “The effectiveness is 0.86.”

Another example, using instrument calibration, has more latitude. If the calibration question was: “Does this instrument meet its accuracy specification?” then a satisfactory answer would be a simple “Yes” or “No.” If, however, the question was “How do the readings of this instrument compare with the true values, over its range?” then an acceptable answer would require a table of values, or a chart, listing the indicated value corresponding to each true value.

Note that a simple request to “Calibrate this instrument” does not establish which of these two answers would be acceptable and does not qualify as a desirable motivating question.