software-quality

2 posts

IBM shipped software with 0.1 defects per KLOC by banning developers from running their own code

IBM's Cleanroom engineering process achieved defect rates 100× better than industry average by preventing bugs instead of finding them.

IBM shipped a NASA satellite control system with 0.1 defects per thousand lines of code. The industry average at the time was between 10 and 50. They did not…

July 23, 2026

fagan-inspections code-review defect-prevention software-quality

Most Code Reviews Catch 20% of Defects. Fagan Inspections Catch 90%.

Informal code review catches 15-30% of defects. Fagan inspections, a structured 50-year-old process, consistently report 60-90% removal rates.

Most code review catches between 15 and 30 percent of the defects it was supposed to find. That is not a guess. IBM measured it in the 1970s, and studies at…

July 10, 2026