Defect Management Process
This is perhaps the activity that is most ignored by organizations today, but offers one of the greatest areas of payback. NASA emphasizes the point that any defect represents a weakness in the process. Seemingly unimportant defects are, from a process perspective, no different than critical defects. It is only the developer's good luck that prevents a defect from causing a major failure. Even minor defects therefore represent an opportunity to learn how to improve the process and prevent potentially major failures. While the defect itself may not be a big deal, the fact that there was a defect is a big deal.
Based on the study's findings, participants should go back to the process that originated the defect to understand what caused the defect. Then they should go back to the validation process that should have caught the defect earlier in the process. Not only can valuable insight be gained as to how to strengthen the review process, this step serves to make everyone involved in these activities take them more seriously. This human factors dimension alone, according to some of the people the research team interviewed, can have a very large impact on the effectiveness of the review process.
NASA, takes an additional step of asking the question: If this defect could have gotten this far into the process before it was captured, what other defects may be present that have not been discovered. Thus not only is the process strengthened to prevent defects, it is strengthened to find defects that have been created, but not yet discovered. This aggressiveness should be mandatory on life critical systems. The well-known "Thearc-25" case of a radiation machine that kept issuing "Malfunction 25" messages is one example where problems might have been caught earlier if this step had been pursued [LEV93].