The cost of defects can be measured by the
impact of the defects and when we find them. Bug repairs start with
requirements and continue through development. After the release, but repairs
and related customer support costs continue until the last user signs off.
If an error is found in the requirement
specification then it is somewhat cheaper to fix it. But if the error is not
caught in the specifications and is not found till the user acceptance, then
cost to fix those errors or defects will be way too expensive.
If, however, a defect is introduced in the
requirement specification and it is not detected until acceptance testing or
even once the system has been implemented then it will be much more expensive
to fix.
Risk of Inadequate testing:
A widely cited study for the National
institute of standards and technology (NIST) reports that inadequate testing
methods and tools annually cost the U.S economy between $22.2 and $59.5 billion.
The same study notes that between 25 and 90 percent of software development
budgets are often spent on testing.