9 basic seven tools of quality

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.


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


(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


(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”)


Step 3 & 4:Step 3 & 4:

Poor Service

Responsiveness

Reliability

Appearance

Attention


Step 5, 6, & 7:Step 5, 6, & 7:

Poor Service

ResponsivenessAppearance

Attention Reliability

time

courtesy

personnelfacility

equipment

One on one service

dependability

accuracy


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.


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.


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::


Positively SkewedPositively Skewed::

Negatively SkewedNegatively Skewed::


Bi-Modal DistributionBi-Modal Distribution::

Multi-Modal DistributionMulti-Modal Distribution::


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?


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”


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?


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


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


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.

9 basic seven tools of quality

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