The Basic Seven (B7) The Basic Seven (B7) Tools of QualityTools of Quality
"As much as 95% of quality related problems in the factory can be solved with "As much as 95% of quality related problems in the factory can be solved with seven fundamental quantitative tools." - Kaoru Ishikawaseven fundamental quantitative tools." - Kaoru Ishikawa
By By Zaipul AnwarZaipul Anwar
Business & Advanced Technology Centre,Business & Advanced Technology Centre,Universiti Teknologi MalaysiaUniversiti Teknologi Malaysia
What are the Basic Seven What are the Basic Seven Tools of Quality?Tools of Quality?
Fishbone DiagramsFishbone Diagrams HistogramsHistograms Pareto AnalysisPareto Analysis FlowchartsFlowcharts Scatter PlotsScatter Plots Run ChartsRun Charts Control ChartsControl Charts
Where did the Basic Where did the Basic Seven come from?Seven come from?
Kaoru IshikawaKaoru Ishikawa Known for “Democratizing Statistics”Known for “Democratizing Statistics”
The Basic Seven Tools made statistical analysis The Basic Seven Tools made statistical analysis less complicated for the average personless complicated for the average person
Good Visual Aids make statistical and quality Good Visual Aids make statistical and quality control more comprehendible.control more comprehendible.
The Basic Seven (B7) The Basic Seven (B7) Tools of QualityTools of Quality
Fishbone DiagramsFishbone Diagrams
No statistics involvedNo statistics involved
Maps out a process/problemMaps out a process/problem
Makes improvement easierMakes improvement easier
Looks like a “Fish Skeleton”Looks like a “Fish Skeleton”
Fishbone (Cause and Effect or Fishbone (Cause and Effect or Ishikawa) Diagrams Ishikawa) Diagrams (1 of 4)(1 of 4)
Named after Kaoru IshikawaNamed after Kaoru Ishikawa Japanese Quality pioneerJapanese Quality pioneer
Resembles skeleton of a fishResembles skeleton of a fish Focus on causes rather than symptoms of Focus on causes rather than symptoms of
a problema problem Emphasizes group communication and Emphasizes group communication and
brainstorming brainstorming Stimulates discussionStimulates discussion
Fishbone (Cause and Effect or Fishbone (Cause and Effect or Ishikawa) Diagrams Ishikawa) Diagrams (2 of 4)(2 of 4)
One of Seven basic tools of Japanese One of Seven basic tools of Japanese QualityQuality
Leads to increased understanding of Leads to increased understanding of complex problemscomplex problems
Visual and presentational toolVisual and presentational tool
Use in Organizations Use in Organizations (1 of 2)(1 of 2)
Can be used to improve any product, Can be used to improve any product, process, or serviceprocess, or service Any area of the company that is Any area of the company that is
experiencing a problemexperiencing a problem Isolates all relevant causesIsolates all relevant causes
Creating Fishbone Creating Fishbone Diagrams Diagrams
(1 of 4)(1 of 4)• As a group:As a group:
1. Establish problem (effect)1. Establish problem (effect)-state in clear terms-state in clear terms-agreed upon by entire -agreed upon by entire
groupgroup
2. Problem becomes the 2. Problem becomes the “head” of the fish“head” of the fish-draw line to head (“backbone”) -draw line to head (“backbone”)
Creating a Fishbone Creating a Fishbone Diagram Diagram
(2 of 4)(2 of 4)3.3. Decide major causes of the Decide major causes of the
problemproblem- by brainstorming- by brainstorming- if the effect or problem is part of a process - if the effect or problem is part of a process the major steps in the process can be usedthe major steps in the process can be used
4. Connect major causes to 4. Connect major causes to backbone of the fish with slanting backbone of the fish with slanting arrowsarrows
Creating a Fishbone Creating a Fishbone Diagram Diagram
(3 of 4)(3 of 4)5. Brainstorm secondary causes 5. Brainstorm secondary causes for each of the major causesfor each of the major causes6. Connect these secondary causes 6. Connect these secondary causes to their respective major causesto their respective major causes7. Repeat steps 5 & 6 for sub-causes 7. Repeat steps 5 & 6 for sub-causes dividing with increased specificity dividing with increased specificity
- usually four or five levels- usually four or five levels
Creating a Fishbone Creating a Fishbone Diagram Diagram
(4 of 4)(4 of 4)8. Analyze and evaluate causes and 8. Analyze and evaluate causes and sub-causessub-causes-may require the use of statistical, analytical, and -may require the use of statistical, analytical, and graphical toolsgraphical tools
9. Decide and take action9. Decide and take action
Example Example (1 of 4)(1 of 4)
Step 1 & 2:Step 1 & 2:
Poor Service(“backbone”)
(“head”)
Example Example (2 of 4)(2 of 4)
Step 3 & 4:Step 3 & 4:
Poor Service
Responsiveness
Reliability
Appearance
Attention
Example Example (3 of 4)(3 of 4)
Step 5, 6, & 7:Step 5, 6, & 7:
Poor Service
ResponsivenessAppearance
Attention Reliability
time
courtesy
personnelfacility
equipment
One on one service
dependability
accuracy
Example Example (4 of 4)(4 of 4)
Step 8 & 9:Step 8 & 9: Use tools to analyze and evaluate causesUse tools to analyze and evaluate causes
Pareto diagrams, charts, and graphsPareto diagrams, charts, and graphs Statistical analysis for causes in processesStatistical analysis for causes in processes
Decide and take actionDecide and take action Use fishbone diagram, analysis and evaluations to Use fishbone diagram, analysis and evaluations to
find causes that can be fixedfind causes that can be fixed Take action to eliminate and fix problem causesTake action to eliminate and fix problem causes
ExerciseExercise Create a Fishbone (cause and effect, Create a Fishbone (cause and effect,
Ishikawa) Diagram for the following:Ishikawa) Diagram for the following:Management at Ham Industries has noticed that Management at Ham Industries has noticed that
the productivity of its workers is well below the standard. the productivity of its workers is well below the standard. After interviewing its employees, it was noticed that a vast After interviewing its employees, it was noticed that a vast majority felt dissatisfied and unhappy with their work. majority felt dissatisfied and unhappy with their work. Your boss has asked you and a group of your peers to find Your boss has asked you and a group of your peers to find the causes of worker dissatisfaction . Include all possible the causes of worker dissatisfaction . Include all possible causes to at least the secondary level.causes to at least the secondary level.
The Basic Seven (B7) The Basic Seven (B7) Tools of QualityTools of Quality
HistogramsHistograms
Bar chartBar chart
Used to graphically represent groups of Used to graphically represent groups of datadata
What is a Histogram?What is a Histogram?
A Histogram is a variation of a bar A Histogram is a variation of a bar chart in which data values are grouped chart in which data values are grouped together and put into different classes. together and put into different classes.
This grouping allows you see how This grouping allows you see how frequently data in each class occur in frequently data in each class occur in the data set.the data set.
What is a Histogram What is a Histogram (cont.)(cont.)
Higher barsHigher bars represent represent more datamore data valuesvalues in a class. in a class.
Lower barsLower bars represent represent fewer datafewer data valuesvalues in a class. in a class.
On the next slide is an example of On the next slide is an example of what a Histogram looks like. what a Histogram looks like.
Example of a HistogramExample of a Histogram
Uses for a Histogram Uses for a Histogram A Histogram can be used:A Histogram can be used: to display large amounts of data values to display large amounts of data values
in a relatively simple chart form.in a relatively simple chart form. to tell relative frequency of occurrence.to tell relative frequency of occurrence. to easily see the distribution of the data.to easily see the distribution of the data. to see if there is variation in the data.to see if there is variation in the data. to make future predictions based on the to make future predictions based on the
data. data.
Where did the Where did the Histogram Come From?Histogram Come From?
The Histogram was first The Histogram was first implemented by Kaoru Isikawa, one implemented by Kaoru Isikawa, one of Japans’ most renowned experts on of Japans’ most renowned experts on quality improvement.quality improvement.
Isikawa spent his life trying to Isikawa spent his life trying to improve quality in Japan. improve quality in Japan.
Where did the Where did the Histogram Come From? Histogram Come From?
(cont.)(cont.) His major contributions to quality His major contributions to quality
improvement are known as the basic improvement are known as the basic seven tools of quality.seven tools of quality.
Included in his basic seven tools of Included in his basic seven tools of quality is the Histogram.quality is the Histogram.
How do Histograms How do Histograms Work?Work?
First, you need need to pick a process to First, you need need to pick a process to analyze.analyze.
Next, you need a large amount of data, at Next, you need a large amount of data, at least 100 data values so that patterns can least 100 data values so that patterns can become visible.become visible.
Then, you need to assemble a table of the Then, you need to assemble a table of the data values that you collected with data values that you collected with regards to frequency of data values.regards to frequency of data values.
How do Histograms How do Histograms Work? (cont)Work? (cont)
Next, you need to calculate some Next, you need to calculate some statistics for the Histogram, including: statistics for the Histogram, including: mean, minimum, maximum, standard mean, minimum, maximum, standard deviation, class width, number of classes, deviation, class width, number of classes, skewness....skewness....
Then, you actually create the Histogram Then, you actually create the Histogram using these statistics. using these statistics.
How do Histograms How do Histograms Work? (cont)Work? (cont)
After you have created a After you have created a Histogram, it will take one of five Histogram, it will take one of five shapes:shapes:
Normal DistributionNormal Distribution::
How do Histograms How do Histograms Work? (cont)Work? (cont)
Positively SkewedPositively Skewed::
Negatively SkewedNegatively Skewed::
How do Histograms How do Histograms Work? (cont)Work? (cont)
Bi-Modal DistributionBi-Modal Distribution::
Multi-Modal DistributionMulti-Modal Distribution::
How do Histograms How do Histograms Work? (cont)Work? (cont)
Once your Histogram is complete, Once your Histogram is complete, you can analyze its shape, as well as you can analyze its shape, as well as the statistics that you came up with. the statistics that you came up with.
This analysis will help you to make This analysis will help you to make better decisions toward quality better decisions toward quality improvements.improvements.
ConstructingConstructing a Histogram a HistogramFrom a set of data computeFrom a set of data compute sumsum mean (x)mean (x) MaxMax MinMin Range (max-min)Range (max-min)
ConstructingConstructing a Histogram a Histogram Use range to estimate beginning and Use range to estimate beginning and
end end Calculate the width of each column Calculate the width of each column
by dividing the range by the number by dividing the range by the number of columnsof columnsRange
# of Columns= Width
Acme Pizza ExampleAcme Pizza Example Let’s say the owner wants a Let’s say the owner wants a
distribution of Acme’s Thursday distribution of Acme’s Thursday Night SalesNight Sales
Data Set from last Thursday(slices)Data Set from last Thursday(slices) 0 2 1 2 2 4 1 3 1 2 1 2 2 4 3 4 1 4 3 2 2 3 2 1 2 2 1 2 2 1 4 2 2 1 2 0 2 1 2 2 4 1 3 1 2 1 2 2 4 3 4 1 4 3 2 2 3 2 1 2 2 1 2 2 1 4 2 2 1 2
1 2 2 1 2 1 2 1 2 1 2 1 2 1 2 2 2 1 2 1 2 1 1 2 2 2 3 1 4 2 2 3 2 2 2 1 2 2 1 2 1 2 1 2 1 2 1 2 1 2 2 2 1 2 1 2 1 1 2 2 2 3 1 4 2 2 3 2 2 2 1 2 3 2 2 4 2 2 4 4 1 2 2 2 3 2 2 1 2 2 4 2 1 2 4 2 1 7 2 1 2 2 3 1 2 1 2 3 2 2 4 2 2 4 4 1 2 2 2 3 2 2 1 2 2 4 2 1 2 4 2 1 7 2 1 2 2 3 1 2 1 1 2 1 2 2 2 1 2 2 1 2 1 2 2 2 4 2 41 1 2 1 2 2 2 1 2 2 1 2 1 2 2 2 4 2 4
Acme Pizza ExampleAcme Pizza ExampleMean = 2.032258 Mean = 2.032258 Max = 7 Max = 7 Min = 0 Min = 0 Range = 7 Range = 7
QuestionQuestionFor 7 columns what would the width be?For 7 columns what would the width be?
Range/Columns=7/7=1 slice
Acme Pizza ExampleAcme Pizza Example
33
65
812
0 0 10
10
20
30
40
50
60
70
1 2 3 4 5 6 7
Slices of Pizza
# tim
es o
r der
edHistogram
Constructing a HistogramConstructing a HistogramHow is this helpful to Acme?How is this helpful to Acme? 2 slices of pizza most common order 2 slices of pizza most common order
placedplaced Distribution of sales useful for forecasting Distribution of sales useful for forecasting
next Thursday’s late night demandnext Thursday’s late night demand
If you were an Acme manager how could If you were an Acme manager how could you apply this information?you apply this information?
The Basic Seven (B7) The Basic Seven (B7) Tools of QualityTools of Quality
Pareto AnalysisPareto Analysis
Very similar to HistogramsVery similar to Histograms
Use of the 80/20 ruleUse of the 80/20 rule
Use of percentages to show importanceUse of percentages to show importance
Pareto Analysis, how to use it
1. Gather facts about the problem, using Check Sheets or Brainstorming, depending on the availability of information.
2. Rank the contributions to the problem in order of frequency.
3. Draw the value (errors, facts, etc) as a bar chart.
4. It can also be helpful to add a line showing the cumulative percentage of errors as each category is added. This helps to identify the categories contributing to 80% of the problem.
5. Review the chart – if an 80/20 combination is not obvious, you may need to redefine your classifications and go back to Stage 1 or 2.
Acme Pizza (Example 1)Acme Pizza (Example 1) SlicesSlices FrequencyFrequency %% 00 11 .3.3
11 33 33 13.09 13.0922 65 65 25.79 25.7933 88 3.17 3.1744 12 12 4.76 4.7655 00 0066 00 0077 11 .3 .3
Acme Pizza (Example 1)Acme Pizza (Example 1) The completed Pareto Analysis results in the following The completed Pareto Analysis results in the following
graph:graph:
0
10
20
30
40
50
60
70
1 2 3 4 5 6 7
Slices of Pizza
# tim
es o
r der
ed
2 1 4 3 7 5 6
Acme Pizza (part 2)Acme Pizza (part 2)Critical ThinkingCritical Thinking
How does the Pareto Analysis differ How does the Pareto Analysis differ from the Histogram?from the Histogram?
How can this be a useful tool to the How can this be a useful tool to the Acme boss?Acme boss?
A series of Pareto charts drill down to more detail
(Example 2) :
Design
ComponentBuild
Other
57 13 4 275.0 17.1 5.3 2.6
75.0 92.1 97.4 100.0
0
10
20
30
40
50
60
70
0
20
40
60
80
100
Defect
CountPercentCum %
Per
cent
Cou
nt
Fault by Main Cause
Connect Module
Torque Motors
Cold Start
Transducer Module
ASIC CalibrationIOP Imon
21 10 8 8 5 3 236.8 17.5 14.0 14.0 8.8 5.3 3.5
36.8 54.4 68.4 82.5 91.2 96.5 100.0
0
10
20
30
40
50
0
20
40
60
80
100
Defect
CountPercentCum %
Perc
ent
Cou
nt
Design Faults
1st level Analysis gives “Design” as main cause of failure
2nd level Analysis gives breakdown of “Design”
The Basic Seven (B7) The Basic Seven (B7) Tools of QualityTools of Quality
FlowchartsFlowcharts
A graphical picture of a PROCESSA graphical picture of a PROCESS
Process Decision
The process flow
FlowchartsFlowchartsDon’t Forget to:Don’t Forget to:
Define symbols before beginningDefine symbols before beginning
Stay consistentStay consistent
Check that process is accurateCheck that process is accurate
Acme Pizza Example Acme Pizza Example (Flowchart)(Flowchart)
WindowWindow Take CustomerTake Customer Money?Money? (start)(start) Order Order
Get PizzaGet Pizza
LockupLockupPut More inPut More in OvenOven 2 Pies 2 Pies Available?Available?
TimeTime to close?to close? Take to CustomerTake to Customer
noyes
no
yesno
yes
How can we use the flowchart to How can we use the flowchart to analyze improvement ideas from analyze improvement ideas from
the Histogram?the Histogram? WindowWindow Take CustomerTake Customer Money?Money?
(start)(start) Order Order
Get PizzaGet Pizza
LockupLockupPut More inPut More in OvenOven 2 Pies 2 Pies Available?Available?
TimeTime to close?to close? Take to CustomerTake to Customer
noyes
no
yesno
yes
Want some practice?Want some practice?Make a flowchart for:Make a flowchart for:
Taking a showerTaking a shower Cooking dinnerCooking dinner Driving a carDriving a car Having a partyHaving a party Creating a FlowchartCreating a Flowchart
Any other processes you can think of?Any other processes you can think of?
The Basic Seven (B7) The Basic Seven (B7) Tools of QualityTools of Quality
Scatter PlotsScatter Plots 2 Dimensional X/Y plots2 Dimensional X/Y plots Used to show relationship Used to show relationship
between independent(x) and between independent(x) and dependent(y) variablesdependent(y) variables
Acme Pizza Acme Pizza (Scatter Diagram)(Scatter Diagram)
Minutes CookingMinutes Cooking Defective PiesDefective Pies1010 114545 883030 557575 20 206060 14 142020 442525 66
In this simple example, you can find the existing In this simple example, you can find the existing relationship without much difficulty but…relationship without much difficulty but…
Scatter DiagramsScatter Diagrams
0
5
10
15
20
25
0 20 40 60 80
•Easier to see direct relationship
Time Cooking (minutes)
Def
ectiv
e Pi
zza s
Scatter DiagramsScatter DiagramsAs a quality toolAs a quality tool
What does this tell Acme What does this tell Acme management about their processes?management about their processes?
Improvements?Improvements?
0
5
10
15
20
25
0 20 40 60 80
Time Cooking (minutes)
Def
e ctiv
e Pi
zzas
The Basic Seven (B7) The Basic Seven (B7) Tools of QualityTools of Quality
Run chartsRun charts Time-based (x-axis)Time-based (x-axis)
CyclicalCyclical
Look for patternsLook for patterns
Run ChartsRun Charts
8 9 10 11 12 1 2 3 4 8 9 10 11 12 1 2 3 4 8 9 10 11 12 1 2 3 4PM- AM PM- AM PM- AM
Thursday
Week 1
Thursday
Week 2
Thursday
Week 3
5 10
15
20 2
5 30
35
40 4
5 50
55
60 6
5 70
75
80 8
5 90
95
100
Slices/hour
Time
The Basic Seven (B7) The Basic Seven (B7) Tools of QualityTools of Quality
Control ChartsControl Charts Deviation from MeanDeviation from Mean
Upper and Lower Spec’sUpper and Lower Spec’s
RangeRange
Control ChartsControl ChartsUpper LimitUpper Limit
Lower LimitLower LimitUnacceptable deviation
X
Control ChartsControl ChartsAcme Pizza Management wants to get in on the control chart action
•Average Diameter = 16 inches
•Upper Limit = 17 inches
•Lower Limit = 15 inches
Acme example Acme example Control ChartsControl Charts
Upper LimitUpper Limit17 inches17 inches
Lower LimitLower Limit15 Inches15 Inches
Small Pie
X16 inches=
Acme example #50Acme example #50Control ChartsControl Charts
•Pies within specifications were acceptable
•One abnormally small pie is “uncommon”
•Should be examined for quality control
Logical Order for B7 Logical Order for B7 ToolsTools
FlowChart
CheckSheet Histograms
ScatterDiagrams
ControlCharts
Cause&
EffectPareto
Analysis
Big Picture
Data Collection
Data Analysis
ProblemIdentification Prioritization
SummarySummary Basic Seven Tools of QualityBasic Seven Tools of Quality
Measuring dataMeasuring data
Quality AnalysisQuality Analysis
““Democratized statistics”Democratized statistics”
BibliographyBibliography Foster, Thomas. Foster, Thomas. Managing Quality. An IntegrativeApproachManaging Quality. An IntegrativeApproach. .
Upper Saddle River : Prentice Hall, Upper Saddle River : Prentice Hall, 2001.2001.
Stevenson, William. “Supercharging Your Pareto Analysis.” Stevenson, William. “Supercharging Your Pareto Analysis.” Quality ProgressQuality Progress October 2000: October 2000: 51-55.51-55.
““Dr Kaoru Ishikawa.” Internet Dr Kaoru Ishikawa.” Internet “http://www.dti.gov.uk/mbp/bpgt/m9ja00001/m9ja0000110.html.” “http://www.dti.gov.uk/mbp/bpgt/m9ja00001/m9ja0000110.html.” 16 February 2001. 16 February 2001.
““Chemical and Process Engineering.” Internet. Chemical and Process Engineering.” Internet. “http://lorien.ncl.ac.uk/ming/spc/spc8.htm.” 17 “http://lorien.ncl.ac.uk/ming/spc/spc8.htm.” 17 February February 2001.2001.
Top Related