3. What is Six Sigma?
High
Probability
of Failure
66807 Defects
Per Million
Opportunities
Much Lower
Probability
of Failure
3.4 Defects
Per Million
Opportunities
6 2’s
1
6 2’s
Mean / Target
Lower
Specification Limit
Upper
Specification Limit
Higher this
number,
Lower the
chance of
producing a
defect
Higher these
numbers,
Lower the
chance of
producing a
defect
1
3 1’s 3 1’s
4. Six Sigma is….3.4 defects per 1000000 opportunities
That means a process efficiency of 99.99966%
LSL USLT
Target
+6-6
USL: Upper Specification Limit for a Performance Standard.
Anything above this is a defect.
LSL: Lower Specification Limit for a Performance Standard.
Anything below this is a defect.
Target: Ideally the middle point of USL & LSL.
In other words, process standard deviation () should be so less that your process
performance can fit within the customer specified limits. So, no matter how much your process
deviates from target, you always meet what customer wants.
5. Cost of Poor Quality
Being Better is Cheaper
Sigma Level Defect per Million Opportunities Cost of Quality
2 308,537 (Non-competitive companies) Not Applicable
3 66,807 25-40% of Sales
4 6,210 (Industry Average) 15-25% of Sales
5 233 5-15% of Sales
6 3.4 (World class) < 1% of Sales
Source: Six Sigma by Mikel Harry
6. μ
σ
What’s in a name?
Sigma is the Greek letter representing the standard
deviation of a population of data.
Sigma is a measure
of variation
(the data spread)
7. What does variation mean?
Variation means that a
process does not produce
the same result (the “Y”)
every time.
Some variation will exist in
all processes.
Variation directly affects customer experiences.
Customers do not feel averages!
-10
-5
0
5
10
15
20
8. Managing Up the Sigma Scale
Sigma % Good % Bad DPMO
1 30.9% 69.1% 691,462
2 69.1% 30.9% 308,538
3 93.3% 6.7% 66,807
4 99.38% 0.62% 6,210
5 99.977% 0.023% 233
6 99.9997% 0.00034% 3.4
11. DMAIC – The Improvement
Methodology
Define Measure Analyze Improve Control
Objective:
DEFINE the
opportunity
Objective:
MEASURE current
performance
Objective:
ANALYZE the root
causes of problems
Objective:
IMPROVE the
process to
eliminate root
causes
Objective:
CONTROL the
process
to sustain the gains.
Key Define Tools:
• Cost of Poor
Quality (COPQ)
• Voice of the
Stakeholder
(VOS)
• Project Charter
• As-Is Process
Map(s)
• Primary Metric
(Y)
Key Measure
Tools:
• Critical to Quality
Requirements
(CTQs)
• Sample Plan
• Capability
Analysis
• Failure Modes
and Effect
Analysis (FMEA)
Key Analyze
Tools:
• Histograms,
Boxplots, Multi-
Vari Charts, etc.
• Hypothesis Tests
• Regression
Analysis
Key Improve
Tools:
• Solution
Selection Matrix
• To-Be Process
Map(s)
Key Control
Tools:
• Control Charts
• Contingency
and/or Action
Plan(s)
12. Green Belts
Use Six Sigma DMAIC methodology and basic
tools to execute improvements within their
existing job function(s)
May lead smaller improvement projects within
Business Unit(s)
Bring knowledge of Six Sigma concepts & tools to
their respective job function(s)
Undergo 8-11 days of training over 3-6 months
13. Black Belts
Use Six Sigma methodologies and advanced tools
(to execute business improvement projects
Are dedicated full-time (100%) to Six Sigma
Serve as Six Sigma knowledge leaders within
Business Unit(s)
Undergo 5 weeks of training over 5-10 months
14. Champions
Promote awareness and execution of Six Sigma
within lines of business and/or functions
Identify potential Six Sigma projects to be
executed by Black Belts and Green Belts
Identify, select, and support Black Belt and
Green Belt candidates
Participate in 2-3 days of workshop training
