1 chapter 12 supplement quality control tools for process improvement 1 chapter 12-supplement...
TRANSCRIPT
1 1
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
Chapter 12-SupplementChapter 12-Supplement
QUALITY CONTROL QUALITY CONTROL TOOLS FOR PROCESS TOOLS FOR PROCESS
IMPROVEMENTIMPROVEMENT
McGraw-Hill/Irwin © 2003 The McGraw-Hill Companies, Inc., All Rights Reserved.
2 2
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
LEARNING OBJECTIVES
• Introduce the basic tools for analyzing processes and quality.
• Describe acceptance sampling and when it can be used to control quality in services.
• Introduce statistical process control and describes how and when it can be used to analyze service processes.
• Define the types of sampling errors that can occur when statistical sampling is used.
• Distinguish between the statistical analysis of attributes and variables.
3 3
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
THE SEVEN BASIC QUALITY TOOLS
• Process Flow Diagrams
• Checksheets
• Histograms/Bar Charts
• Pareto Charts
• Scatterplots
• Run Charts
• Cause-and-Effect Diagrams
4 4
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
Exhibit 12S.1PROCESS FLOW DIAGRAM: DRYCLEANING SERVICE
Pay in advance?
Requestreceipt
Acceptpayment
Pickingup?
Give clothesTo customer;
Verify ownership
yes
no
Droppingoff?
CheckClothing/
Complete form
Getclothes
no
yesGreetcustomer
Providereceipt
yes
end
no
Give farewellgreeting
startPay in
advance?
Requestreceipt
Acceptpayment
Pickingup?
Give clothesTo customer;
Verify ownership
yes
no
Droppingoff?
CheckClothing/
Complete form
Getclothes
no
yesGreetcustomer
Providereceipt
yes
end
no
Give farewellgreeting
start
5 5
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
Exhibit 12S.3CHECKSHEET
Count
1
2
3
4
5
6
>6
Customers
In PartyCount
Location question
Rate question
Complaint
Reservation
Service question
Guest call
Other
Call Type Count
1
2
3
4
5
6
>6
Customers
In PartyCount
Location question
Rate question
Complaint
Reservation
Service question
Guest call
Other
Call Type
6 6
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
Exhibit 12S.4EXAMPLE OF A BAR CHART
Country of Origin of Customers During Lunch Thursday June 10
02468
10121416
US
Ind
ia
Ko
rea
Ja
pa
n
Fra
nce
Arg
en
tin
a
Le
ba
no
n
Fre
qu
en
cy
Country of Origin of Customers During Lunch Thursday June 10
02468
10121416
US
Ind
ia
Ko
rea
Ja
pa
n
Fra
nce
Arg
en
tin
a
Le
ba
no
n
Fre
qu
en
cy
7 7
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
Exhibit 12S.5EXAMPLE OF A HISTOGRAM
0
2
4
6
85 10
15
20
25
30
35
40
Fre
qu
en
cy
Time to Take Order
Seconds
0
2
4
6
85 10
15
20
25
30
35
40
Fre
qu
en
cy
Time to Take Order
Seconds
8 8
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
Exhibit 12S.6EXAMPLE OF A PARETO CHART
0
2
4
6
8
10
12
14
16
18
Fre
qu
enc
y
0%
20%
40%
60%
80%
100%
Cu
mu
lati
ve P
erce
nt
proc
ed
ure
s
spac
e
pat
ien
ts
ED
Sta
ff
Hos
pita
l st
aff
equ
ipm
ent
Survey Responses: Factors Requiring Change
0
2
4
6
8
10
12
14
16
18
Fre
qu
enc
y
0%
20%
40%
60%
80%
100%
Cu
mu
lati
ve P
erce
nt
proc
ed
ure
s
spac
e
pat
ien
ts
ED
Sta
ff
Hos
pita
l st
aff
equ
ipm
ent
Survey Responses: Factors Requiring Change
0
2
4
6
8
10
12
14
16
18
Fre
qu
enc
y
0%
20%
40%
60%
80%
100%
Cu
mu
lati
ve P
erce
nt
proc
ed
ure
s
spac
e
pat
ien
ts
ED
Sta
ff
Hos
pita
l st
aff
equ
ipm
ent
Survey Responses: Factors Requiring Change
9 9
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
Exhibit 12S.8EXAMPLE OF A SCATTERPLOT
01
23
456
78
910
0 2 4 6 8 10 12 14
Waiting Time to Order (minutes)
Sa
tisf
acti
on
01
23
456
78
910
0 2 4 6 8 10 12 14
Waiting Time to Order (minutes)
Sa
tisf
acti
on
10 10
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
Exhibit 12S.9EXAMPLE OF A RUN CHART
Arrival Time
Wait
Tim
e,
min
ute
s
10
:00
p.m
.
Average Waiting Time for a Table
6:3
0 p
.m.
7:0
0 p
.m.
7:3
0 p
.m.
8:3
0 p
.m.
8:0
0 p
.m.
9:3
0 p
.m.
9:0
0 p
.m.
6:0
0 p
.m.
30
20
10
40
60
50
70
Arrival Time
Wait
Tim
e,
min
ute
s
10
:00
p.m
.
Average Waiting Time for a Table
6:3
0 p
.m.
7:0
0 p
.m.
7:3
0 p
.m.
8:3
0 p
.m.
8:0
0 p
.m.
9:3
0 p
.m.
9:0
0 p
.m.
6:0
0 p
.m.
30
20
10
40
60
50
70
11 11
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
Exhibit 12S.10EXAMPLE OF A CAUSE-AND-EFFECT DIAGRAM Server Attitude Waits
Food Environment
Rude
Too many tables
Confused
Inadequate training
Long waits for check
Uncomfortable wait for table
Food served cold
Server notificationsystem inadequate
Cold dining area
Soiled carpets
Inadequatehousekeepertraining
DissatisfactionWith Experience
Server Attitude Waits
Food Environment
Rude
Too many tables
Confused
Inadequate training
Long waits for check
Uncomfortable wait for table
Food served cold
Server notificationsystem inadequate
Cold dining area
Soiled carpets
Inadequatehousekeepertraining
Server Attitude Waits
Food Environment
Rude
Too many tables
Confused
Inadequate training
Long waits for check
Uncomfortable wait for table
Food served cold
Server notificationsystem inadequate
Cold dining area
Soiled carpets
Inadequatehousekeepertraining
DissatisfactionWith Experience
Server Attitude Waits
Food Environment
Rude
Too many tables
Confused
Inadequate training
Long waits for check
Uncomfortable wait for table
Food served cold
Server notificationsystem inadequate
Cold dining area
Soiled carpets
Inadequatehousekeepertraining
12 12
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
Exhibit 12S.11THE EIGHT STEP QUALITY IMPROVEMENT PROCESSPDCA # STEP/DESCRIPTION TOOLS
P 1 Identify the Problem
L Collect Data
A Analyze the Problem
N Scatterplots Pareto Charts
Histograms/Bar ChartsFlow Charts Run Charts
Identify Cause-and-EffectRoot Causes Diagrams
Develop a solutionAnd action plan
DO
C Scatter PlotsH Pareto ChartsE HistogramsC Flow ChartsK Run Charts
Control Charts
A FlowchartsC Control chartsT
2 Checksheets
3 Analyze the Problem
4
5 Flowcharts
6
Implement the Solution
7 Review and Evaluate
8
Standardize the Process
13 13
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
TWO BASIC MODELS FOR STATISTICAL QUALITY CONTROL
• Acceptance Sampling: This involves testing samples after the goods or services have been produced.
• Statistical Process Control: This involves testing samples of goods or services as they are being produced.
14 14
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
Exhibit 12S.12THE RELATIONSHIP BETWEEN POPULATION QUALITY AND SAMPLE FINDINGS
Good Lot Accepted: No
Error
Bad Lot Accepted: Type II Error or
Good Lot Rejected: Type II
Error or
Bad Lot Rejected: No Error
What the Population Quality Actually Is
Good
Bad
Wh
at
the S
am
ple
Fin
din
g I
s
Goo
dB
ad
15 15
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
Exhibit 12S.13OPERATING CHARACTERISTIC CURVE
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
OC Curve: N = 100, n = 15, c = 1
Actual Percent Defective (d)
0 51 2 3 4 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
OC Curve: N = 100, n = 15, c = 1
Actual Percent Defective (d)
0 51 2 3 4 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
16 16
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
Exhibit 12S.14THE NORMAL DISTRIBUTION
68.26%
95.44%
99.73%
+1s +2s +3s-2s -1s-3s
17 17
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
PROCESS CAPABILITY
1. Collect data on the process while the process is operating without known causes of variation.
2. Compare the customer’s requirements to the inherent variation of the process.
18 18
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
Exhibit 12S.16CAPABILITY STUDY
Process is not capable: Specifications are well within 3 s.Much of the output of the process will not meet the customer’s requirements.
+3s-3s Mean=12
specifications
process variation
Process is Capable: Specifications are outside 3 s.Virtually all of the output of the process will meet the customer’s requirements.
+3s-3s Mean=12
specifications
process variation
(A) (B)Process is not capable: Specifications are well within 3 s.Much of the output of the process will not meet the customer’s requirements.
+3s-3s Mean=12
specifications
process variation
Process is Capable: Specifications are outside 3 s.Virtually all of the output of the process will meet the customer’s requirements.
+3s-3s Mean=12
specifications
process variation
(A) (B)
19 19
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
Exhibit 12S.17SIX-SIGMA QUALITY
-3s
specifications
+3sMean
process variation
-6s +6s
20 20
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
Exhibit 12S.20CHANGES IN MEAN AND DISPERSION OF SAMPLE MEAN DISTRIBUTIONS
Shift in mean of distribution Shift in dispersion of distribution.Shift in mean of distribution Shift in dispersion of distribution.
21 21
Chapter 12 Supplemen
t
Quality Control Tools for Process Improvement
KEY TERMS
• Acceptance Sampling• Capability• Central Limit Theorem• Operating Characteristic Curve• Statistical Process Control• Type I Error• Type II Error• Variables