A study by Capers Jones reports that even the best software development organizations are only 85 percent effective in removing bugs. The problem here is that QA professionals often have no idea of the internal structure of the code and don't know that such error handling code exists. Then there's the problem of creating the tests in the first place, which can be a significant development effort. And with the way Web-based applications seem to undergo redesigns every six months, it's not clear how much value there is in creating automated tests that may soon be obsolete. First, look for alternative methods that complement conventional testing.
Conventional testing is often the only way to discover intent errors.
But the existence of these cases is completely hidden from the test designer. According to Capers Jones, nearly two-thirds of all defects fall into this category. What's needed are ways to find these code-level errors early in the development cycle. Studies show that inspection is more efficient and cost-effective than conventional testing. Similarly, project leaders and managers, challenged by ambitious product development schedules, see writing code as productive and reading code as a time waster.