The 7 Basic Quality Tools

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The 7 Basic Quality Tools

• Michele Cano

2
Agenda

• Introductions
• The 7 Basic Tools
• Exercises
• Break
• The 7 Basic Tools continued
• Exercises
• Group Discussions

3
What are they?

• The seven basic tools according to Ishikawa are
• Check sheets
• Flow charts
• Graphs Histograms
• Pareto diagram
• Cause and effect diagram
• Scatter diagram
• Control chart

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Why use tools?

• To make data visible
• Measure
• Improve

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1.Check sheets

• What is a check sheet?
• A form or sheet used to record data.

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Function of Check Sheets

• According to Ishikawa 1982, check sheets have the
  following functions
• Production Process distribution checks
• Defective item checks
• Defective location checks
• Defective cause checks
• Check-up confirmation checks
• Others

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Example of a simple check sheet. (for car valet
operation)
Car type Car registration Ford Focus W357 PHR
Interior vacuumed v
Upholstery cleaned v
Dash board cleaned v
De odorised v
Body washed v
Washed waxed Polished v
Under car washed v
Wheels washed v
Tyres blacked v
Comments Front bumper badly scratched on delivery, this can not be covered Comments Front bumper badly scratched on delivery, this can not be covered
Performed / Checked by J Bloggs Date 2 May 2008
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Example of a simple process check sheet.
(attributes)
Model XYZC217 Batch Batch Batch Batch Batch Batch Batch Batch Batch Batch
failures 1 2 3 4 5 6 7 8 9 10
Power up 1 2 1              
Boot up 6 4 2 1         2  
Sink test 2   1     1     1  
Case damage   1   1     2      
Keyboard damage                    
Monitor damaged     1       2      
Bundled s/w included   3     1         3
Checked by pj am jj j lm lm rm pj am pj
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FlowchartsPROCESS MAPPING

• Process mapping is an essential first step.
• It identifies all of the process activities,
  sequence and responsibilities.
• This can either be in a written format, or as a
  flowchart.

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FlowchartsPROCESS MAPPING (Written format)
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Flowcharting

• Flowcharting is a graphical tool for analysing
  processes.
• Constructing flowcharts leads to a better
  understanding of processes.
• Better understanding of processes is a essential
  for improvement

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FlowchartsSome standard symbols
Start or end
An activity
a decision point in the process.
a point at which the flowchart connects with another process.
An off page connection
All records are identified
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FLOWCHART
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HACCP

• Hazard Analysis and Critical Control Points
• Businesses are required to identify any step
  in the activities of the food business which is
  critical to ensuring food safety and ensure that
  adequate safety procedures are identified,
  implemented, maintained, and reviewed.

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Steps involved in HACCP

1. Identify the Hazard
2. Identify points when you need to have control
   measures (control points)
3. Decide what control measures are needed
4. Implement those controls
5. Monitor

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Exercise

• Draw / evaluate a flowchart for one of the
  following processes
• Making a cup of coffee or tea
• Cutting the grass
• Booking a flight on-line
• Organising a surprise birthday party

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3. Graphs Histograms

• Graphs, in various forms are used to aid
  understanding and analysis of collected data
  sets.

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GraphsBAR CHARTS

• This is the data set shown graphically.
• It highlights the major problems for all to see.

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Graphs

• This graph shows production output for February.

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Graphs

• The graph below shows categories of customer
  complaint.

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Rules for Graphing

• Use titles and indicate when the data was
  collected
• Ensure the scales are clear and represent the
  data accurately.
• Always keep in mind the reason why the graph is
  being used.

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Exercise Graphs

• You are the marketing director of XZY automotive,
  a new Scottish company. You have organised a
  local survey to rate your car against other small
  cars.
• 30 people were polled and the results are shown
  below.
• Xzy, ka, Clio, Clio, ka, fiesta, xzy, ka, 206,
  xzy, fiesta, fiesta, xzy, polo, fiesta, 206, 206,
  polo, 206, fiesta, fiesta, fiesta, polo, xzy,
  polo, fiesta, xzy, xzy, ka, xzy.
• You have decided to Graph the results as part of
  your marketing drive. Choose and explain your
  choice of graph.

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What is a Histogram?

• The Histogram shows the distribution of one
  characteristic for one period of time.

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What is a Histogram?

• Is this a histogram?

Checks/only record failures Total
Power up 4
Boot up 15
Sink test 5
Case damage 4
Keyboard damage 0
Monitor damaged 3
Bundled s/w included 7
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What is a Histogram?

• The answer to the previous question is NO
• The Histogram shows the distribution of one
  characteristic for one period of time.

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When is a Histogram Used?

• To look at one particular set of results, for one
  characteristic at one period of time
• To look for patterns in a process
• To help understand data

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Histograms

• The following data was collected when measuring
  the bow (warp) of a plastic component. The
  specification is less than 8 x10-3 mm (zero 8).
• This can be plotted as a histogram because we
  have quantitative data and target limits.

Bow measurements Bow measurements
2 5 8 8 2
4 6 6 6 4
4 7 6 6 4
8 7 7 5 9
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Histograms
Bow Frequency
0 0
1 0
2 2
3 0
4 4
5 2
6 5
7 3
8 3
9 1
0
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What is a Histogram?

• Exercise
• Sort the data about male weights into appropriate
  sets, then plot a histogram.

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4. Pareto Analysis

• Separating the vital few from the trivial
  many Juran

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What is Pareto Analysis?

• Pareto analysis is a method to help prioritise
  actions.
• It is a Bar Chart displayed in a particular way
  either in order of importance (frequency,
  relative cost, etc).

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ParetoExample
The information to be represented on a Pareto
diagram normally would have already been
collected.
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ParetoPareto Chart
The data are then displayed graphically. Firstly
in terms of frequency.....
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Pareto ... and then by cost.
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Exercise Produce a Pareto Diagram
for the data in the separate handout.
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6. Cause and Effect Diagrams (Ishikawa) using
brainstorming

• A method to help identification of the root
  causes of an effect (usually a problem).

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cause and effectWhat is Brainstorming?

• A way to get creative ideas.
• A way to get everyones views.
• A way to generate alternatives.

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cause and effectPotential Uses (Brainstorming)

• For identifying areas for improvement.
• For finding potential causes of problems.
• For developing possible preventive actions.

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cause and effectSome Guidelines
(Brainstorming)
Dos Don'ts

• Give wild and unusual ideas.
• Aim for quantity.
• Build on ideas of others.
• Encourage participation.

• Evaluate or criticise.
• Stop to soon.
• Allow domination or idea ownership.

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Simple Rules for Brainstorming

• 1. Works best with a group of six to twelve
  members.
• 2. Ideas are taken from one member at a time, in
  rotation.
• 3. Ideas are written on a flip chart or OHP
  transparency.
• 4. If a response is not immediately forthcoming
  the member should pass.
• 5. No idea is too obvious or stupid.

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Simple Rules for Brainstorming

• 6. Ideas should not be enlarged upon at this
  stage.
• 7. The leader is there to lead the group, not to
  provide ideas.
• 8. The process is repeated until ideas dry up.
• 9. The ideas are then discussed and can be
  criticised but not the people that made them.
• 10. Eliminate the unlikely causes and identify
  those with high possibilities using cause
  screening - put those on a fishbone diagram.

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Ranking

• Group discussion of likely causes and ease of
  fixing.
• Individual selection of 3-5 most likely.
• Paired comparisons

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Group discussion (Ranking)

• Group discusses if each possible cause is
• N Not likely
• S - Somewhat likely
• V - Very likely
• And the ease of fixing
• N - Not easy
• S - Somewhat easy
• V - Very easy

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cause and effectIndividual Ranking

• Each person privately selects 3 - 5 items from
  the list
• Each person ranks their selection in order of
  priority
• Allocate values of 1 most important, 2 next, 3
  next,
• The marks are then totalled for each item
• The item having the lowest total is then judged
  to
• have the highest priority.

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Paired Comparisons

• The group preselects 6 8 most important causes.
• Each person completes a paired comparison grid.
• Scores are added using a vote matrix.
• Highest score is most important

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No. ITEM ITEM ITEM ITEM ITEM ITEM
1 1 2 1 3 1 4 1 5 1 6
2 2 3 2 4 2 5 2 6
3 3 4 3 5 3 6
4 4 5 4 6
5 5 6
6
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ITEM NO. TEAM MEMBER VOTES TOTAL RANK
1
2
3
4
5
6
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cause and effectWhat is a Cause and Effect
Diagram?

• The process of a cause and effect diagram
  consists of defining an effect in terms of
  possible causes and is normally carried out in
  the form of a Brainstorming session.
• The principal causes are typically Man,
  Materials, Methods or Machines. However you can
  also use Environment, Marketing, Management,
  Money etc. depending upon the exact situation.

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Cause and Effect Analysis

• sub-causes can then be added
• Finally, the most likely causes are then
  identified for further investigation.
• These relationships are displayed pictorially in
  the form of a fishbone structure.

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cause and effect Layout
Method
Man
Sub-Cause
Sub-Cause
Sub-Cause
Effect
Sub-Cause
Sub-Cause
Sub-Cause
Materials
Machines
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Using Three Cause and Effect Diagrams

1. Present situation
2. Desired final situation
3. How to get from the present to the desired.

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6. Scatter Diagrams

• A method for the identification of a possible
  relationship between two factors.

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Scatter diagramsWhat is it used for?

• Validating "hunches" about a possible
  cause-and-effect relationship between two
  variables.
• Displaying the direction of the possible
  relationship (positive, negative, etc.)
• Displaying the strength of the possible
  relationship

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Scatter diagramsConstructing scatter diagram

• In order to construct a scatter diagram you need
  two variables to be plotted against each other.
  One on the x-axis the other on the y-axis.
• Different values of variable b are then plotted
  against variable a.

Variable b
Variable a
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Scatter diagramsConstructing scatter diagram

• This process is continued, plotting different
  values as one variable changes.

Variable b
Variable a
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Scatter diagramsInterpreting a scatter diagram

• The diagram below shows a Strong Positive
  correlation between the variables.

Variable b
Variable a
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Scatter diagramsInterpreting a scatter diagram

• The diagram below shows a Strong Negative
  correlation between the variables.

Variable b
Variable a
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Scatter diagramsInterpreting a scatter diagram

• The diagram below shows a Weak Positive
  correlation.

Variable b
Variable a
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Scatter diagramsInterpreting a scatter diagram

• The diagram below shows a Weak Negative
  correlation.

Variable b
Variable a
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Scatter diagramsInterpreting a scatter diagram

• The diagram below shows no correlation between
  the variables.

Variable b
Variable a
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NOTE

• It is an important note that any positive or
  negative correlation does not mean that there is
  a cause and effect relationship between the
  variables.
• Only that there might be!

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7. Control Charts

• A method for monitoring a process for preventing
  defects.
• Covered in a separate session by Esteban
  Fernandez

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Problem Solving

• Steps
• Define Problem
• Collect Data
• Display Data
• Analyse results
• Consider possible causes
• Identify possible solutions
• Experiment
• Implement and follow up

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Problem Analysis
Problem Identification
Flow chart Check sheet Brainstorming
Histogram Scatter Diagram
Cause and effect Pareto SPC
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Problem Solving methods

• 5 Why
• Global 8D
• TRIZ

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What is 5 Why

• 5 Whys is a problem solving technique that
  allows you to get at the root cause of a problem
  fairly quickly.
• It is used by automotive industry in Japan to
  determine the root cause of problems.

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• Most problems do not call for complex
  statistical analysis but instead require
  painstaking, detailed problem solving
• This requires a level of detailed thinking and
  analysis that is all too absent from most
  companies in day to day activity
• Yuichi Okamoto
• Toyota technical Centre

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What is 5 Why?

• The 5 Why technique is a very simple method of
  getting to the root of a problem
• When a problem occurs, we ask.WHY?until the
  root cause is found. Five times is usually enough
  to get to the root of the problem!

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Advantages

• If the correct Why questions are asked in
  succession to the correct people he or she will
  find at least one root cause of the problem.
• It only takes short time to perform i.e. 5 to 10
  mins
• There are no special tools or software required.
• It can make people have a new way of thinking out
  problems.

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Disadvantages

• It usually only leads to one of the root causes
  so need to repeat the process
• Sometimes you need to go through process several
  times to find all the causes which can require
  some skill from the question maker.
• It does not always point you in the direction of
  generic causes e.g. training issues.

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Heres How It Works!!!
Man is late for work

• PROBLEM

WHY?
Because his car stopped
WHY?
Because it ran out of petrol
WHY?
Because he did not buy any on the way to work
WHY?
Because he had no money
WHY?
Because he lost it all in a game of poker

Solution Stop playing poker!!!!
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Global 8D

• D0 Prepare
• D1 Use the team approach
• D2 Describe the problem
• D3 Implement and verify interim containment
  action
• D4 Identify and Verify root causes
• D5 Choose and Verify corrective action
• D6 Implement Corrective Action
• D7 Prevent recurrence close the loop
• D8 Recognition