This document summarizes a workshop on control charts for management. The workshop will teach participants how to interpret control charts and explain their benefits. Control charts were invented in the 1920s to distinguish between common and special causes of variation in processes. The workshop will cover the components and interpretation of control charts, why they are important for monitoring processes, and how they benefit management by showing when processes are stable or in need of intervention.

1. Control Chart Workshop
for Management
http://www.gbna.ca

2. Learning Objectives
At the end of this workshop, you will be able
to:
Interpret your control chart
Explain the benefits of a control chart
Would you like to gain something else from
this session?
© 2012 Gilles Bélanger & Associates Inc. 2

3. The Origin of the
Control Charts
Control Charts were invented by Walter A Shewart while working for
Bell Labs in the 20’s.
• He developed a theory that there are two components to
variation:
• Common Cause: random and predictable
• Special Cause: non-random and assignable cause that could be
internal or external to the system
Over the next 50 years, Dr. W. Edwards Deming became the
biggest proponent of Shewart’s work.
• His definition of Special Cause is: non-random and unusual
event external to the system
© 2012 Gilles Bélanger & Associates Inc. 3

4. Key Discussion Points
What is a control chart and what are its
components?
Why is the control chart important for me and
what is it telling me?
It provides a clear signal when management
intervention is required.
© 2012 Gilles Bélanger & Associates Inc. 4

5. Shewhart’s contribution
Control chart illustrates process behavior over
time
It’s a special cause detection tool
Can also be used as a predictive tool when
the process is stable
© 2012 Gilles Bélanger & Associates Inc. 5

6. Components of a
Control Chart
Upper and
Lower
Data Mean control Limit
is always are shown.
shown
They reflect
the Voice of
the
Process.
© 2012 Gilles Bélanger & Associates Inc. 6

7. Components of a
Control Chart
Upper and
Lower
control
limits Upper Spec
represents limit defined
±3 by
standard management
deviations. or a third
Standard party.
deviation is
a measure
of variation.
The data in above control chart are within the control limits. The
process is stable and predictable. We can predict there is a 99.7%
probability the next data point will be between 4.13 and 5.95).
© 2012 Gilles Bélanger & Associates Inc. 7

8. Components of a
Control Chart
Upper Control
Limit (ULC): 3σ
Lower Control
σ= SIGMA-Letter from the Greek alphabet used in Limit (LCL): -3σ
statistics as a symbol for standard deviation
© 2012 Gilles Bélanger & Associates Inc. 8

9. Components of a
Control Chart
Mean
Lower Control Limit Upper Control Limit
Normal distribution (symmetrical) :
68% of data points are contained within ±1σ,
95% of data points are contained within ± 2 σ,
99.7% of data points are contained within ± 3 σ (UCL & LCL).
© 2012 Gilles Bélanger & Associates Inc. 9

10. Components of a
Control Chart
When all data
points are
within the
Control Limits
we have
common
cause,
routine,
Normal random
distribution variation.
Special cause conditions are unusual, non-random events, external to the
system. When one or several data points are outside the Control Limits, the
process is Out of Control and management attention is required.
© 2012 Gilles Bélanger & Associates Inc. 10

11. Components of a
Control Chart
What can you conclude about the profit goal?
© 2012 Gilles Bélanger & Associates Inc. 11

12. Why is a Control Chart important for me?
1. Allows you to see patterns and trends over time
2. Make a distinction between special causes and common causes
of variation
3. May be used as a tool for ongoing control of process
4. Warns you when a problem or a shift in the process has
occurred
5. Provides a common language for discussing process
performance
Control chart is a tool that helps you to effectively monitor process
performance metrics and support you and your team in better
managing improved processes by validating their stability, predictability
and performance.
© 2012 Gilles Bélanger & Associates Inc. 12

13. Why is a Control Chart important for me?
Customers may be
How your internal or external.
Customer feels
the process
Happy
Happy
employees! Stability Predictability
Customers!
Is your process stable
and predictable over
Control Chart time?
© 2012 Gilles Bélanger & Associates Inc. 13

14. What is a Control Chart telling me?
Special cause: Special cause:
investigate, investigate
possible
temporary
process shift?
Common
cause: do
not react.
Control chart shows the “Voice of the Process” and tells you when to keep going
or stop and investigate for a special cause!
© 2012 Gilles Bélanger & Associates Inc. 14

15. What is a Control Chart telling me?
Upper and Lower Control Limits are determined by the process and not by
management or third party specifications
© 2012 Gilles Bélanger & Associates Inc. 15

16. What is a Control Chart telling me?
BEFORE After your
Before any
improvement team’s process
we have an improvement
average wait project, we can
time of 11 predict there is
minutes a 99.7%
probability the
next data point
AFTER will be between
6.89 and 11.19
minutes. New
average is 9
minutes!
© 2012 Gilles Bélanger & Associates Inc. 16

17. Control Chart benefits
Summary
No more firefighting.
Better resource
React only to special
management!
causes that are outside
Happier employees! the Voice of the Process
Control Limits!
Higher quality of
work, no
surprises.
© 2012 Gilles Bélanger & Associates Inc. 17

18. Questions?
Please email any question to: gbelanger@gbna.ca
© 2012 Gilles Bélanger & Associates Inc. 18