A 1995 report by Capers Jones, "Software Quality for 1995: What Works and What Doesn't," forSoftware Productivity Research, gives the performance of the four most common defect removal practices in the industry today: formal design and code inspections, formal quality assurance, and formal testing. The efficiency of bug removal for these methods used individually is as follows:
Formal design inspections 45%-68%
Formal software testing 37%-60%
Formal quality assurance 32%-55%
No formal methods at all 30%-50%
When taken in combination:
Formal design inspections and formal code inspections 70%-90%
The best combination:
Formal design inspections, formal quality assurance, formal testing 77%-95%
