Page 211 - Lean six sigma demystified

Chapter 5 Redu C ing d efe C t S with Six Sigm a 189

prove their pet theory or justify their actions. Only after a long struggle do
they begin to learn how to use data as a guide to clear thinking and action.
I’ve always liked the quote: “He uses statistics like a drunk uses a light
post, for support not illumination.” In Lean Six Sigma this holds true far
too often.
Knowing what to measure and how to measure it makes a complicated
world much less so. If you learn how to look at data in the right way, you
can explain riddles that otherwise might have seemed impossible. Compa-
nies generate lots of data about orders, sales, purchases, payments, and so
on. The bigger the company, the more data they have and the less likely
they are to use it. Figure out what data is useful and use it. Figure out what
data isn’t useful and stop collecting it.
2. Ask quirky questions. If you’re focused on why things go wrong, ask: “What
are we doing right? Who is already doing this right?” If you focus on why
things are going right, focus on what’s wrong and start with the “worst
first.” In Freakonomics, Levit stopped asking why crime rates have fallen
since 1990. He started asking what kind of individuals are most likely to
commit crimes and then asked, “Why are they disappearing from the pop-
ulation?” His answer to that question is startling, but instructive of his
method: “Let the data lead you.”
3. Don’t mistake correlation for causality. The United States spends 2.5 times
more on health care than any other country, yet Americans aren’t health-
ier than other countries. Affluent women have a higher incidence of breast
cancer than poor women. Does wealth cause breast cancer? Does health
care cause illness?
Dramatic effects often have distant, even subtle, causes. Six Sigma looks for

direct causes and effects, but systemic effects can amplify subtle causes
into dramatic ones.
4. Question conventional wisdom. The conventional wisdom is often wrong. If
conventional wisdom were correct, then most problems would have
already been solved. You can’t get new insights from old ways of thinking.
5. Respect the complexity of incentives. Incentives are the cornerstone of mod-
ern life. In Lean Six Sigma people are rewarded for following systems that
cause defects, delays, and cost. Humans will always find ways to beat the
system. Rely on it.

The moral of the story: “Make data your friend,” says Hopkins. I’d say let it
be your guide.