CHAPTER 3: QUALITY IMPROVEMENT
Outline
• Process improvement
– PDSA cycle
– Process improvement steps
– Tools
1
The P-D-S-A Cycle
Plan
Do
Identify problem. Develop
plan for improvement.
Implement plan
on test basis
Act
Institutionalize improvement.
Continue cycle.
Study
Is the plan working?
2
Steps in Process Improvement
• Plan
1: Recognize problem
2: Form quality improvement teams
3: Define problem
4: Develop performance measures
5: Analyze problem
6: Determine possible causes
3
Steps in Process Improvement
• Do
7: Implement solution
• Study
8: Evaluate solution
• Act
9: Ensure performance
10: Continuous improvement
4
Plan: Steps 1 and 2
1: Recognize problem
– Existence of the problem is outlined
– In general terms, specifics are not clearly defined
– Solvability and availability of resources are
determined
2: Form quality improvement teams
– Interdisciplinary
– Specified time frame
– Quality circle
5
Plan: Step 3
3: Define the problem
– Define the problem and its scope
– Pareto analysis
– Brainstorming
– Why-why diagram
6
Number of defects
50
100
40
80
30
60
20
40
10
20
0
0
Cumulative percentage
Pareto Chart
7
Pareto Chart
40
100
80
C
30
60
20
40
10
20
D
A
0
Cumulative percentage
Number of defects
50
B
0
Defect type
8
Pareto Chart
40
100
80
C
30
60
20
40
10
20
D
A
0
Cumulative percentage
Number of defects
50
B
0
Defect type
9
70
Pareto Chart
(64)
Percent from each cause
60
50
40
30
20
(13)
10
(10)
(6)
(3)
0
Causes of poor quality
(2)
(2)
Why-Why Diagram
• A technique to understand the problem
• Does not locate a solution
• The process leads to many reasons the original
problem occurred
• Example: A mail-order company has a goal or
reducing the amount of time a customer has to wait in
order to place an order. Create a why-why diagram
about waiting on the telephone.
11
Why-Why Diagram
Waiting
on
the
Why?
phone
to place
an order
Why?
Why?
Insufficient
operators
available
Many customers
calling at the
same time
Why?
Why?
Workers not
scheduled at
peak times
Low pay
All catalogs
shipped at
the same
time
12
Plan: Step 4
4: Develop performance measures
– Set some measurable goals which will indicate
solution of the problem
– Some financial measures: costs, return on
investment, value added, asset utilization
– Some customer-oriented measures: response
times, delivery times, product or service
functionality, price
– Some organization-oriented measures: employee
retention, productivity, information system
capabilities
13
Plan: Steps 5 and 6
5: Analyze problem
– List all the steps involved in the existing process
and identify potential constraints and opportunities
of improvement
– Flowchart
6: Determine possible causes
– Determines potential causes of the problem
– Cause and effect diagrams, check sheets,
histograms, scatter diagrams, control charts, run
charts
14
Flowchart
Operation
Delay
Storage
Transportation
Inspection
Decision
Enter emergency room
Flowchart
Fill out
patient
history
Walk to
triage
room
Nurse
inspects
injury
Return to
Wait
waiting for ER bed
room
Walk to
ER bed
Walk to
Radiology
Doctor
inspects
injury
Wait
for
doctor
Walk to radiology
Flowchart
Technician
Return to Wait for
X-rays
ER bed doctor to
patient
return
Doctor
provides
diagnosis
Return
to
Waiting
Leave
Building
Pickup
prescription
Walk to
pharmacy Checkout
Cause and Effect Diagram
• Common categories of problems in manufacturing
– 5 M’s and an E
• Machines, methods, materials, men/women,
measurement and environment
• Common categories of problems in service
– 3 P’s and an E
• Procedures, policies, people and equipment
18
Cause and Effect Diagram
Measurement
Faulty testing equipment
Incorrect specifications
Improper methods
Inaccurate
temperature
control
Dust and Dirt
Environment
Men/Women
Machines
Out of adjustment
Poor supervision
Lack of concentration
Tooling problems
Inadequate training
Old / worn
Quality
Problem
Defective from vendor
Not to specifications
Materialhandling problems
Materials
Poor process design
Ineffective quality
management
Deficiencies
in product design
Methods
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Check Sheet
COMPONENTS REPLACED BY LAB
TIME PERIOD: 22 Feb to 27 Feb 1998
REPAIR TECHNICIAN: Bob
TV SET MODEL 1013
Integrated Circuits
Capacitors
Resistors
Transformers
Commands
CRT
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Frequency of calls
Histogram
40
35
30
25
20
15
10
5
0
1 2
6 13 10 16 19 17 12 16 20 17 13
5 6 2
Telephone call duration, min
1
Number of tears
Scatter Diagram
.
Rotor speed, rpm
Control Chart
27
Number of defects
24
UCL = 23.35
21
c = 12.67
18
15
12
9
6
LCL = 1.99
3
2
4
6
8
10
12
Sample number
14
16
Do: Step 7
7: Implement the solution
– The solution should
• prevent a recurrence of the problem
• address the root cause of the problem
• be cost effective
• be implemented within a reasonable amount
of time
– Force-field analysis
24
Do: Step 7
– Force-field analysis
• A chart that lists
– the positive or driving forces that
encourages improvement as well as
– the restraining forces that hinders
improvement
– Actions necessary for improvement
25
Do: Step 7
Example: create a force-field diagram for the
following problem:
– Bicycles are being stolen at a local campus.
Campus security is considering changes in the
bike rack design, bike parking restrictions and
bike registration to try to reduce thefts. Thieves
have been using hacksaws and bolt cutters to
remove locks from the bikes
26
Reading
• Chapter 3:
– Reading pp. 64-97 (2nd ed.), pp. 52-102 (3rd ed.)
27