8D vs A3 vs 6-Sigma

I get asked this question at least once a month by quality managers: should we use 8D, A3, or Six Sigma? The honest answer is most companies choose whichever the boss read about last week. That leads to a six-month Black Belt project on a problem that should have been a two-week 8D. A Tier 2 supplier had a persistent seal leak with 3 percent field failure rate. The new Quality Director just returned from Green Belt training and made it a DMAIC project. Two months in Define and Measure — process maps, Gage R&R, project charter, financial sign-off — fourteen people with weekly steering meetings. They spent over 1,000 engineering hours before Analyze found the root cause in two days: a worn seal on the test fixture scarring O-rings during assembly. A forty-dollar seal replacement and a daily check. A fishbone and 5-Why on the production floor would have found it in one afternoon. The customer saw us spinning for four months while we defined and measured things they did not care about. Six Sigma is an optimization engine not a firefighting tool. When a customer has a problem right now they want containment in 24 hours, root cause...