Asking The Wrong Question
©2020, George J. Irwin. All rights reserved.
One reason why the Define Phase of the classic DMAIC model (Define, Measure, Analyze, Improve, Control) is so important is this: it should uncover whether you’re asking the right question... or the wrong question.
An historic example of this, quoted frequently inside and outside Black Belt Land, is the study of the location of bullet holes in Allied aircraft returning from missions during World War II. The story goes that since there were bullet holes in the wings and elsewhere, it was concluded that there needed to be reinforcements to those parts of the aircraft.
No, said a mathematician named Abraham Wald. I’m not sure he said “You’re asking the wrong question,” but he did point out that the analysis was only on the planes that came back from combat. Where there were not bullet holes was the place to focus, for if planes were hit in those areas, they didn’t make it back.
As you can read elsewhere online, the incoming aircraft analysis is an example of what’s called “survivorship bias.” Fortunately, most wrong questions are not asked in life-or-death situations. Even so, it’s important to think carefully through whether the problem presented to you and the Lean Six Sigma Project Team is really the right problem to be solved.
So how does one figure out whether the right question is being asked? There are several approaches. I think the most direct one is a cause and effect diagram. Start with the problem as written and then connect as many steps as necessary to get to the impact on one or more of cost, lost revenue, customer satisfaction, rework, missed targets, and so on. A single straight A to B line may mean that the “problem” is just a symptom, not the actual root causal issue that needs to be addressed.
This is not only not easy sometimes, it’s tricky. Whether we Lean Six Sigma Practitioners like it or not, we’re the outsiders on the project team. That can make the pointing out of a new direction for a project a delicate activity. One (hopefully!) diplomatic approach to this is reminding the team that there is an investment in time and resources which would be put to optimal use solving the right problem.
There are also the fortunately infrequent times when the discovery of the Wrong Question takes place well beyond the Define Phase of the project. This news is not usually taken well by the project team, let alone its Sponsor and Champion. That’s why a thorough vetting of the problem statement is so important at the outset, as well as understanding whether your stakeholders will be comfortable with a change of direction.