1

CHAPTER 3: QUALITY IMPROVEMENT

Outline

• Process improvement – PDSA cycle– Process improvement steps– Tools

2

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

7

Pareto Chart

Nu

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100

80

60

40

20

0

50

40

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20

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0

Cu

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ge

8Defect type

C

DA B

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100

80

60

40

20

0

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40

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Pareto Chart

9

Nu

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100

80

60

40

20

0

50

40

30

20

10

0

Cu

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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

27

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.)