Ah yes, Six Sigma. That overhyped load of BS. I went through that in the factory I worked at back in the 90s. We made great improvements at our plant AFTER we convinced management to stop wasting so much time training employees on the wonders of R bars, bell curves, PONC status, standard deviation, flow charts, etc.
and get back to basics!
What we did was simple. Identify a problem area, get a group of 4 or 5 people who worked in that area, meet once a week, & follow the steps posted on a plaque in our cafeteria since 1975.
1: Identify root cause.
2: Take corrective action.
3: Follow up/monitor
No BS like Six Sigma required.
I wouldn't throw the baby out with the bath water. The basics/principals of the Six Sigma approach were valid and could reap big rewards. Of course, any place might go about it badly, use it blindly, etc. Like anything, it's about the implementation, and your specific needs.
In our case, applying statistics to each of those three steps made it much more powerful and effective. You don't just identify/correct/monitor, but you analyze the variation and attempt to keep the values centered and minimize variation to the greatest extent practical, and identify what might be standing in the way. You identify the root causes of the variation (long term drift, random drift or drift with a bias, short term noise, temperature, time, etc?). All that forces you to understand the process, rather than just putting in corrective action, seeing good results, declaring it 'fixed', when you may have missed some of the other causes that, if corrected, might keep the problem from coming back over time. It was good discipline, IMO.
No love for Mr Welch though. I've heard enough about his destructive ways.
I'm reminded of a quote from the TV show "The Office", the usually awful boss, Michael Scott said, in one of his occasional bits of insight when one of his employees screwed up and thought he'd be fired: "A good boss doesn't fire people, he inspires people".
-ERD50