SIX SIGMA A MEASURE OF QUALITY FOR ORGANIZATIONS
What
is Six Sigma?
Six Sigma at many organizations
simply means a measure of quality that strives for near perfection. It can be
called “Six Sigma,” or it may have a generic or customized name for the
organization like “Operational Excellence,” “Zero Defects,” or “Customer Perfection.”
Six Sigma is a disciplined, data-driven approach and methodology for
eliminating defects (driving toward six standard deviations between the mean
and the nearest specification limit) in any process – from manufacturing to
transactional and from product to service.
The
Six Sigma DMAIC process (define, measure, analyze, improve, control) is an
improvement system for existing processes falling below specification and
looking for incremental improvement.
How Six
Sigma Began
In the
19th century, German mathematician and physicist Carl Fredrich Gauss developed
the bell curve. By creating the concept of what a normal distribution looks
like, the bell curve became an early tool for finding errors and defects in a
process.
In the
1920s, American physicist, engineer and statistician Walter Shewhart expanded
on this idea and demonstrated that “sigma imply where a process needs
improvement,” according to “The Complete Business Process Handbook:
Body of Knowledge From Process Modeling to BPM Vol. 1” by Mark von Rosing,
August-Wilhelm Scheer and Henrik von Scheel.
In the
1980s, Motorola brought Six Sigma into the mainstream by using the methodology
to create more consistent quality in the company’s products, according to “Six Sigma” by Mikel Harry and Richard Schroeder.
Motorola
engineer Bill Smith eventually became one of the pioneers of modern Six Sigma,
creating many of the methodologies still associated with Six Sigma in the late
1980s. The system is influenced by, but different than, other management
improvement strategies of the time, including Total Quality Management and Zero Defects.
Does it
work? Motorola reported in 2006 that the company had saved $17 billion using
Six Sigma.
What Six
Sigma Means
Experts
credit Shewhart with first developing the idea that any part of process that
deviates three sigma from the mean requires improvement. One sigma is one standard deviation.
The Six
Sigma methodology calls for bringing operations to a “six sigma” level, which
essentially means 3.4 defects for every one million opportunities. The goal is
to use continuous process improvement and refine processes until they produce
stable and predictable results.
Six Sigma
is a data-driven methodology that provides tools and techniques to define and
evaluate each step of a process. It provides methods to improve efficiencies in
a business structure, improve the quality of the process and increase the
bottom-line profit.
The
Importance of People in Six Sigma
A key
component of successful Six Sigma implementation is buy-in and support from
executives. The methodology does not work as well when the entire organization
has not bought in.
Another
critical factor is the training of personnel at all levels of the organization.
White Belts and Yellow Belts typically receive an introduction to process
improvement theories and Six Sigma
terminology. Green Belts typically work for Black Belts on
projects, helping with data collection and analysis. Black Belts lead projects
while Master Black Belts look
for ways to apply Six Sigma across an organization.
Methodologies
of Six Sigma
There are
two major methodologies used within Six Sigma, both of which are composed of
five sections, according to the 2005 book “JURAN Institute Six Sigma
Breakthrough and Beyond” by Joseph A. De Feo and William Barnard.
DMAIC: The DMAIC method is used primarily for
improving existing business processes. The letters stand for:
- Define the problem and the
project goals
- Measure in detail the various
aspects of the current process
- Analyze data to, among other
things, find the root defects in a process
- Improve the process
- Control how the process is
done in the future
DMADV: The DMADV method is typically used to
create new processes and new products or services. The letters stand for:
- Define the project goals
- Measure critical components
of the process and the product capabilities
- Analyze the data and develop
various designs for the process, eventually picking the best one
- Design and test details of
the process
- Verify the design by running
simulations and a pilot program, and then handing over the process to the
client
There are
also many management tools used within Six Sigma. Some examples include the
following.
Five Whys
This is a
method that uses questions (typically five) to get to the root cause of
a problem. The method is simple: simply state the final problem (the
car wouldn’t start, I was late to work again today) and then ask the question
“why,” breaking down the issue to its root cause. In these two cases, it might
be: because I didn’t maintain the car properly and because I need to leave my
house earlier to get to work on time.
CTQ Tree
The Critical to Quality (CTQ) Tree diagram
breaks down the components of a process that produces the features needed in
your product and service if you wish to have satisfied customers.
Root
Cause Analysis
Much like
the Five Whys, this is a process by which a business attempts to identify the
root cause of a defect and then correct it, rather than simply correcting the
surface “symptoms.”
All the
Six Sigma tools and methodologies serve one purpose: to streamline business
processes to produce the best products and services possible with the smallest
number of defects. Its adoption by corporations around
the globe is an indicator of its remarkable success in today’s business
environment.
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