chapter 3: quality improvement
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1
CHAPTER 3: QUALITY IMPROVEMENT
Outline
• Process improvement – PDSA cycle– Process improvement steps– Tools
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The P-D-S-A Cycle
Identify problem. Develop plan for improvement.
Institutionalize improvement. Continue cycle.
Is the plan working?
Plan
Act
Study
DoImplement plan on test basis
3
• Plan
1: Recognize problem
2: Form quality improvement teams
3: Define problem
4: Develop performance measures
5: Analyze problem
6: Determine possible causes
Steps in Process Improvement
4
• Do
7: Implement solution
• Study
8: Evaluate solution
• Act
9: Ensure performance
10: Continuous improvement
Steps in Process Improvement
5
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
Plan: Steps 1 and 2
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3: Define the problem– Define the problem and its scope – Pareto analysis– Brainstorming– Why-why diagram
Plan: Step 3
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Pareto Chart
Nu
mb
er o
f d
efec
ts
100
80
60
40
20
0
50
40
30
20
10
0
Cu
mu
lati
ve p
erce
nta
ge
8Defect type
C
DA B
Nu
mb
er o
f d
efec
ts
100
80
60
40
20
0
50
40
30
20
10
0
Cu
mu
lati
ve p
erce
nta
ge
Pareto Chart
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Nu
mb
er o
f d
efec
ts
100
80
60
40
20
0
50
40
30
20
10
0
Cu
mu
lati
ve p
erce
nta
ge
Defect type
C
DA B
Pareto Chart
Per
cent
fro
m e
ach
caus
e
Causes of poor quality
Mac
hine
cal
ibra
tions
Defec
tive
parts
Wro
ng d
imen
sions
Poor D
esig
n
Ope
rato
r erro
rsDef
ectiv
e m
ater
ials
Surfa
ce a
bras
ions
0
10
20
30
40
50
60
70(64)
(13)(10)
(6)(3) (2) (2)
Pareto Chart
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• 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.
Why-Why Diagram
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Why-Why Diagram
Waiting onthe
phone to placean order
Many customers calling at the same time
All catalogs shipped at the same
time
Insufficient operatorsavailable
Low pay
Workers not scheduled at peak times
Why?
Why?
Why?
Why?
Why?
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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
Plan: Step 4
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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
Plan: Steps 5 and 6
Flowchart
Operation
Storage
Inspection
Delay
Transportation
Decision
FlowchartEnter emergency room
Fill out patient history
Walk totriage room
Nurse inspects
injury
Return towaitingroom
Wait for ER bed
Wait for
doctor
Doctor inspects
injury
Walk toER bed
Walk toRadiology
FlowchartWalk to radiology
TechnicianX-rayspatient
Return toER bed
Wait fordoctor to
return
Doctorprovidesdiagnosis
CheckoutPickup
prescription
Return to
Waiting
LeaveBuilding
Walk topharmacy
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• 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
Cause and Effect Diagram
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Cause and Effect Diagram
QualityProblem
MachinesMeasurement Men/Women
MethodsEnvironment Materials
Faulty testing equipment
Incorrect specifications
Improper methods
Poor supervision
Lack of concentration
Inadequate training
Out of adjustment
Tooling problems
Old / worn
Defective from vendor
Not to specifications
Material-handling problems
Deficienciesin product design
Ineffective qualitymanagement
Poor process design
Inaccuratetemperature control
Dust and Dirt
Check Sheet
COMPONENTS REPLACED BY LABTIME PERIOD: 22 Feb to 27 Feb 1998REPAIR TECHNICIAN: Bob
TV SET MODEL 1013
Integrated Circuits ||||
Capacitors |||| |||| |||| |||| |||| ||
Resistors ||
Transformers ||||
CommandsCRT |
Histogram
0
510152025303540
1 2 6 13 10 16 19 17 12 16 20 17 13 5 6 2 1
Telephone call duration, min
Fre
quen
cy o
f ca
lls
Scatter Diagram
.
Rotor speed, rpm
Num
ber
of t
ears
Control Chart
18
12
6
3
9
15
21
24
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2 4 6 8 10 12 14 16Sample number
Num
ber
of d
efec
ts
UCL = 23.35
LCL = 1.99
c = 12.67
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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
Do: Step 7
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– 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
Do: Step 7
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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
Do: Step 7
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Reading
• Chapter 3: – Reading pp. 64-97 (2nd ed.), pp. 52-102 (3rd ed.)
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