Christopher Alexander describes setting up a quality measure for each
requirement.
"The idea is for each requirement to have a quality measure that makes it
possible to divide all solutions to the requirement into two classes: those
for which we agree that they fit the requirement and those for which we
agree that they do not fit the requirement."
In other words, if we specify a quality measure for a requirement, we mean
that any solution that meets this measure will be acceptable. Of course it is
also true to say that any solution that does not meet the measure will not be
acceptable.
The quality measures will be used to test the new system against the
requirements. The remainder of this paper describes how to arrive at a quality
measure that is acceptable to all the stakeholders.
