DMAIC works — on processes
Define, Measure, Analyze, Improve, Control. I ran it for 17 years on processes, and it holds. But every failed project had the same missing step: nobody investigated the human pattern running the process.
The unmeasured input
A control chart tells you when a process drifts. But people drift too — the supervisor who quietly re-prioritizes, the team that learned which corners are safe. Behavior is an unmeasured input in almost every process you run.
Behavioral RCA
Root cause analysis asks “five whys” — but usually stops at “because the person did X.” The real root is why doing X made sense to them. That is where Six Sigma meets behavioral investigation.
The One Action: Take your worst recurring defect. Ask why until you reach a human decision. Then ask why that decision made sense.