Cutting through the Six Sigma hype.
There’s a lot of hype surrounding Six Sigma these days. As we risk losing our grip on what it is all about, let's spend some time discussing what Six Sigma is and what it is not.
By Gary Cone
What Six Sigma is:
A Philosophy. The philosophy can be boiled down to the GPS slogan
– “better tomorrow than today.” My interpretation of
this slogan is that we can define the critical processes of our business,
we understand the few critical measures of those processes, and we
are always commissioning “adhoc” teams to pursue the next
improvement opportunity - always. Six Sigma has the potential to be
a vision tool or to paraphrase Tom Peters, a tool to get the herd
generally headed west.
A Benchmarking Metric. To calculate this metric is the only purpose for defining and counting opportunities in a consistent manner. We convert defect data to DPMO or sigma measures strictly for the ability to benchmark. This is why it is important to know your control capability (note this is quite different from saying put control charts on everything) and know that it is within a reasonable range. We benchmark to know who to learn from and where to go apply resources. The sigma metric is only a management tool.
A Roadmap For Improvement. This is taught as “Black Belt” training. It doesn’t matter if we call it MAIC, DMAIC, GETS (Gather, Evaluate, Transform, and Sustain or GE Transportation Systems as you prefer), or PCOR (Prioritize, Characterize, Optimize, and Realize from our friends at Air Academy). Anybody who gets hung up on the words is just as guilty as the Shainin devotees – letting labels get in the way of progress. What’s important is that we have a common toolset that is attuned to our changing needs as we learn about and improve our critical processes. If the toolset does not have enough tools to achieve benchmark results, learn which ones are missing and add to the toolset. Tools – useable and used best describes this approach. This means do not close your mind to new tools, just have a rigorous criteria for acceptance of the new tools. The person who suggests new tools must demonstrate the usefulness (application) and the benefit (results) to the organization. The Six Sigma toolset should be understood by any professional tasked with running a process, not just the people we are isolated from the process called “Black Belts.”.
What Six Sigma is not:
It is not a substitute for a good Quality System. Six Sigma maps sub
processes; the Quality System should demand an accurate map of every
critical process. Six Sigma evaluates the Measurement System of sub
processes whereas the QUALITY SYSTEM should demand that every Measurement
System is qualified prior to use (this includes accurate instructions
and training for everyone involved). Six Sigma will put training,
procedures, metrics, and so on in place where they are found to be
lacking. The Quality System should have this disciplined practice
already in place. In short, much of what is called Six Sigma these
days is just sticking fingers in the leaky dike of a poor Quality
System. “Improve constantly and forever the system of production
and service” – Deming’s point number 5. This should
be the mission and the structure of the Quality System. Six Sigma
is meant to augment it, not be a substitute for it.
It is not to be used to the exclusion of other known improvement tools. Lean Enterprise principles should be the first toolset that comes to mind. Should we map the value stream and remove obvious waste before starting Six Sigma? Should we embrace the ideas of SMED at the same time we are targeting processes? Is there less opportunity for defects in small inventories or large inventories? I hope the answers are obvious.
It is not a substitute for training your people in basic job skills.
If you go into a project and find people doing the same job differently,
figure out why the job is not clearly defined and why the people are
not properly trained. Your biggest gain will be right there. If you
find people constantly tweaking a process, talk them into not adjusting
the process and it will usually settle right down. Then, go find out
why the people were not properly trained.
It is not a substitute for having a disciplined product development
process and rigorous management reviews. People are paying big bucks
for DFSS these days where the existing process is haphazard, lacking
simple metrics, absent of consequence for not achieving launch targets.
Why? Go define the process you are really going to follow. Think about
DFSS a year or so later.
The bottom line is that most companies waving the Six Sigma flag are actually defining processes and training people for the first time. You don’t need Six Sigma to do that. You just need clear thinking. Use the Six Sigma approach to further improve once you have the basics in place.
