The Basic Seven (B7) Tools of Quality

1
The Basic Seven (B7) Tools of Quality

• "As much as 95 of quality related problems in
  the factory can be solved with seven fundamental
  quantitative tools." - Kaoru Ishikawa

By Zaipul AnwarBusiness Advanced Technology
Centre,Universiti Teknologi Malaysia
2
What are the Basic Seven Tools of Quality?

• Fishbone Diagrams
• Histograms
• Pareto Analysis
• Flowcharts
• Scatter Plots
• Run Charts
• Control Charts

3
Where did the Basic Seven come from?

• Kaoru Ishikawa
• Known for Democratizing Statistics
• The Basic Seven Tools made statistical analysis
  less complicated for the average person
• Good Visual Aids make statistical and quality
  control more comprehendible.

4
The Basic Seven (B7) Tools of Quality

• Fishbone Diagrams
• No statistics involved
• Maps out a process/problem
• Makes improvement easier
• Looks like a Fish Skeleton

5
Fishbone Diagram Overview (1 of 2)

• Definition
• Uses
• Ishikawa
• Use within organizations
• benefits
• Creation of the Diagram
• Steps 1-9

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Fishbone Diagram Overview (2 of 2)

• Example
• Service example
• Exercise
• Ham Industries

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Fishbone (Cause and Effect or Ishikawa) Diagrams
(1 of 4)

• Named after Kaoru Ishikawa
• Japanese Quality pioneer
• Resembles skeleton of a fish
• Focus on causes rather than symptoms of a problem
• Emphasizes group communication and brainstorming
• Stimulates discussion

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Fishbone (Cause and Effect or Ishikawa) Diagrams
(2 of 4)

• One of Seven basic tools of Japanese Quality
• Leads to increased understanding of complex
  problems
• Visual and presentational tool

9
Fishbone (Cause and Effect or Ishikawa) Diagrams
(3 of 4)

• Typically done on paper or chalkboard
• Recently some computer programs have been created
  to make Fishbone Diagrams
• Ishikawa Environment

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Use in Organizations (1 of 2)

• Can be used to improve any product, process, or
  service
• Any area of the company that is experiencing a
  problem
• Isolates all relevant causes

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Use in Organizations (2 of 2)

• Helps bring a problem into light
• Group discussion and brainstorming
• Finds reasons for quality variations, and the
  relationships between them

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Creating Fishbone Diagrams (1 of 4)

• As a group
• 1. Establish problem (effect)
• -state in clear terms
• -agreed upon by entire group
• 2. Problem becomes the head of the fish
• -draw line to head (backbone)

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Creating a Fishbone Diagram (2 of 4)

• Decide major causes of the problem
• - by brainstorming
• - if the effect or problem is part of a process
  the major steps in the process can be used
• 4. Connect major causes to backbone of the fish
  with slanting arrows

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Creating a Fishbone Diagram (3 of 4)

• 5. Brainstorm secondary causes for each of the
  major causes
• 6. Connect these secondary causes to their
  respective major causes
• 7. Repeat steps 5 6 for sub-causes dividing
  with increased specificity
• - usually four or five levels

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Creating a Fishbone Diagram (4 of 4)

• 8. Analyze and evaluate causes and sub-causes
• -may require the use of statistical, analytical,
  and graphical tools
• 9. Decide and take action

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Example (1 of 4)

• Step 1 2

Poor Service
(backbone)
(head)
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Example (2 of 4)

• Step 3 4

Responsiveness
Appearance
Poor Service
Reliability
Attention
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Example (3 of 4)

• Step 5, 6, 7

Responsiveness
Appearance
time
equipment
personnel
facility
Poor Service
accuracy
One on one service
courtesy
dependability
Reliability
Attention
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Example (4 of 4)

• Step 8 9
• Use tools to analyze and evaluate causes
• Pareto diagrams, charts, and graphs
• Statistical analysis for causes in processes
• Decide and take action
• Use fishbone diagram, analysis and evaluations to
  find causes that can be fixed
• Take action to eliminate and fix problem causes

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Summary (1 of 3)

• Fishbone Diagrams
• - visual diagram
• - resembles fish skeleton
• - identifies the causes of a problem (effect),
  and their relationships
• - created by Kaoru Ishikawa for Quality
  Management

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Summary (2 of 3)

• Organizational Uses
• Increases communication about problems
• Used to improve any product, process, or service
• Important part of quality management

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Summary (3 of 3)

• Creation of Fishbone diagrams
• Problem or effect is head of fish
• Identify major, secondary and tertiary causes,
  and attach to backbone identifying relationships
• Analyze and Evaluate results
• Act to fix the problem(s)

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Exercise

• Create a Fishbone (cause and effect, Ishikawa)
  Diagram for the following
• Management at Ham Industries has noticed that
  the productivity of its workers is well below the
  standard. After interviewing its employees, it
  was noticed that a vast majority felt
  dissatisfied and unhappy with their work. Your
  boss has asked you and a group of your peers to
  find the causes of worker dissatisfaction .
  Include all possible causes to at least the
  secondary level.

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Bibliography

• //home.t-online.de/home/kfmaas/q_ishika.html
• www.zi.unizh.ch/software/unix/statmath/sas/sasdoc/
  qc/chap17/sect1.htm
• www.dti.gov.uk/mbp/bpgt/m9ja00001/m9ja0000110.html
  
• Foster, S. Thomas. Managing Quality An
  Integrative Approach. 2001, Prentice-Hall

25
The Basic Seven (B7) Tools of Quality

• Histograms
• Bar chart
• Used to graphically represent groups of data

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Overview

• What is a Histogram?
• What are some possible uses for a Histogram?
• Where did the Histogram come from?
• How do Histograms work?
• A real world example.
• An exercise.

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What is a Histogram?

• A Histogram is a variation of a bar chart in
  which data values are grouped together and put
  into different classes.
• This grouping allows you see how frequently data
  in each class occur in the data set.

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What is a Histogram (cont.)

• Higher bars represent more data values in a
  class.
• Lower bars represent fewer data values in a
  class.
• On the next slide is an example of what a
  Histogram looks like.

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Example of a Histogram

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Uses for a Histogram

• A Histogram can be used
• to display large amounts of data values in a
  relatively simple chart form.
• to tell relative frequency of occurrence.
• to easily see the distribution of the data.
• to see if there is variation in the data.
• to make future predictions based on the data.

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Where did the Histogram Come From?

• The Histogram was first implemented by Kaoru
  Isikawa, one of Japans most renowned experts on
  quality improvement.
• Isikawa spent his life trying to improve quality
  in Japan.

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Where did the Histogram Come From? (cont.)

• His major contributions to quality improvement
  are known as the basic seven tools of quality.
• Included in his basic seven tools of quality is
  the Histogram.

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How do Histograms Work?

• First, you need need to pick a process to
  analyze.
• Next, you need a large amount of data, at least
  100 data values so that patterns can become
  visible.
• Then, you need to assemble a table of the data
  values that you collected with regards to
  frequency of data values.

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How do Histograms Work? (cont)

• Next, you need to calculate some statistics for
  the Histogram, including mean, minimum, maximum,
  standard deviation, class width, number of
  classes, skewness, and kurtosis.
• Then, you actually create the Histogram using
  these statistics.

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How do Histograms Work? (cont)

• After you have created a Histogram, it will take
  one of five shapes
• Normal Distribution

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How do Histograms Work? (cont)

• Positively Skewed
• Negatively Skewed

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How do Histograms Work? (cont)

• Bi-Modal Distribution
• Multi-Modal Distribution

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How do Histograms Work? (cont)

• Once your Histogram is complete, you can analyze
  its shape, as well as the statistics that you
  came up with.
• This analysis will help you to make better
  decisions toward quality improvements.

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Constructing a Histogram

• From a set of data compute
• sum
• mean (x)
• Max
• Min
• Range (max-min)

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Constructing a Histogram

• Use range to estimate beginning and end
• Calculate the width of each column by dividing
  the range by the number of columns

Range
Width
of Columns
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Acme Pizza Example

• Lets say the owner wants a distribution of
  Acmes Thursday Night Sales
• 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 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 1 2 1 2 2 2 1 2 2 1 2 1 2 2 2 4 2
  4

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Acme Pizza Example

• Mean 2.032258
• Max 7
• Min 0
• Range 7
• Question
• For 7 columns what would the width be?

Range/Columns7/71 slice
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Acme Pizza Example
Histogram
times ordered
Slices of Pizza
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Constructing a Histogram

• How is this helpful to Acme?
• 2 slices of pizza most common order placed
• Distribution of sales useful for forecasting next
  Thursdays late night demand
• If you were an Acme manager how could you apply
  this information?

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The Basic Seven (B7) Tools of Quality

• Pareto Analysis
• Very similar to Histograms
• Use of the 80/20 rule
• Use of percentages to show importance

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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.

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Acme Pizza (Example 1)

• Slices Frequency
• 0 1 .3
• 1 33 13.09
• 2 65 25.79
• 3 8 3.17
• 4 12 4.76
• 5 0 0
• 6 0 0
• 7 1 .3

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Acme Pizza (Example 1)

• The completed Pareto Analysis results in the
  following graph

times ordered
2
1
4
3
7
5
6
Slices of Pizza
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Acme Pizza (part 2)

• Critical Thinking
• How does the Pareto Analysis differ from the
  Histogram?
• How can this be a useful tool to the Acme boss?

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A series of Pareto charts drill down to more
detail (Example 2)
1st level Analysis gives Design as main cause
of failure
2nd level Analysis gives breakdown of Design
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The Basic Seven (B7) Tools of Quality

• Flowcharts
• A graphical picture of a PROCESS

Process
Decision
The process flow
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Flowcharts

• Dont Forget to
• Define symbols before beginning
• Stay consistent
• Check that process is accurate

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Acme Pizza Example (Flowchart)

• Window Take Customer Money?
• (start) Order
• Get Pizza
• Lockup
• Put More in
• Oven 2 Pies
• Available?
• Time
• to close?
• Take to Customer

yes
no
no
yes
no
yes
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How can we use the flowchart to analyze
improvement ideas from the Histogram?

• Window Take Customer Money?
• (start) Order
• Get Pizza
• Lockup
• Put More in
• Oven 2 Pies
• Available?
• Time
• to close?
• Take to Customer

yes
no
no
yes
no
yes
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Want some practice?

• Make a flowchart for
• Taking a shower
• Cooking dinner
• Driving a car
• Having a party
• Creating a Flowchart
• Any other processes you can think of?

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The Basic Seven (B7) Tools of Quality

• Scatter Plots
• 2 Dimensional X/Y plots
• Used to show relationship between independent(x)
  and dependent(y) variables

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Acme Pizza (Scatter Diagram)

• Minutes Cooking Defective Pies
• 10 1
• 45 8
• 30 5
• 75 20
• 60 14
• 20 4
• 25 6
• In this simple example, you can find the
  existing relationship without much difficulty but

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Scatter Diagrams

• Easier to see direct relationship

Defective Pizzas
Time Cooking (minutes)
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Scatter Diagrams

• As a quality tool
• What does this tell Acme management about their
  processes?
• Improvements?

Defective Pizzas
Time Cooking (minutes)
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The Basic Seven (B7) Tools of Quality

• Run charts
• Time-based (x-axis)
• Cyclical
• Look for patterns

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Run Charts
Slices/hour
5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85
90 95 100
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 4
Time
PM- AM
PM- AM
PM- AM
Thursday Week 1
Thursday Week 2
Thursday Week 3
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The Basic Seven (B7) Tools of Quality

• Control Charts
• Deviation from Mean
• Upper and Lower Specs
• Range

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Control Charts

• Upper Limit
• Lower Limit

X
Unacceptable deviation
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Control Charts

• Acme Pizza Management wants to get in on the
  control chart action
• Average Diameter 16 inches
• Upper Limit 17 inches
• Lower Limit 15 inches

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Acme example Control Charts

• Upper Limit
• 17 inches
• Lower Limit
• 15 Inches

X
16 inches
Small Pie
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Acme example 50Control Charts

• Pies within specifications were acceptable
• One abnormally small pie is uncommon
• Should be examined for quality control

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Logical Order for B7 Tools
Big Picture
Data Collection
Data Analysis
ProblemIdentification
Prioritization
FlowChart
CheckSheet
Histograms
CauseEffect
ParetoAnalysis
ScatterDiagrams
ControlCharts
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Summary

• Basic Seven Tools of Quality
• Measuring data
• Quality Analysis
• Democratized statistics

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Bibliography

• Foster, Thomas. Managing Quality. An
  IntegrativeApproach. Upper Saddle River
  Prentice Hall, 2001.
• Stevenson, William. Supercharging Your Pareto
  Analysis. Quality Progress October 2000
  51-55.
• Dr Kaoru Ishikawa. Internet http//www.dti.go
  v.uk/mbp/bpgt/m9ja00001/m9ja0000110.html. 16
  February 2001.
• Chemical and Process Engineering. Internet.
  http//lorien.ncl.ac.uk/ming/spc/spc8.htm. 17
  February 2001.