Chapter%207%20Quality%20Tools

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Chapter 7Quality Tools
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Which tool is best?

• Tools can serve as the backbone for virtually any
  type of quality improvement effort (Six Sigma,
  TQM, 8D)
• Graphical representations of data help us
  understand the true importance of data.
• There is no single one-size fits all solution.
  Every project and problem is different.

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Diagnostic Tools

• Analytical Tools
• Cause-Effect (CE) diagram
• Failure mode-effects Analysis (FMEA)
• XY matrix
• Affinity diagram
• Fault tree analysis (FTA)

• Graphical Tools
• Histogram
• Boxplots
• Probability distribution plots
• Main-effects plots
• Pareto charts
• Run charts
• Multi-Vari charts
• Time-series plots
• Scatter plots

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Diagnostic Tools

• Other Tools
• Checksheets
• Scorecards

• Graphical Rep. of Process
• Process flow charts
• Process mapping
• Cross-functional mapping
• Deployment diagram
• Supplier-input-process-output-customer (SIPOC)
  diagram
• Input-process-output (IPO) diagram
• Force-field analysis

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Problem Definition

• A good problem definition will include quantified
  information about the problem, the magnitude of
  the problem, the baseline, and the gap remaining
  to reach a benchmark or desired state
• Be Specific
• Use declarative format
• Quantify
• Be factual
• Example of poor problem definition Reduce
  restorable time for severity 1 telephone banking
  problems, focusing on human errors as root cause
• Example of good problem definition Reduce
  restorable time from 51 per month for severity 1
  telephone banking problems to 30 or less per
  month by the third quarter of this year,
  resulting in annual savings of 4.5M

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Y f (x)

• The transfer equation of Yf(x) where X x1, x2,
  x3,,xn recognizes that a causal relationship
  exits in any process of action performed.
• Y is a function of one or many xs where Y is the
  dependent variable and the xs are independent
  variables.
• X can equal quality, delivery time, cost of the
  product. Therefore Critical to Satisfaction
  refers to any variable that has significant
  influence on one of more of the determinants of
  customer satisfaction.
• Pareto principal suggests that 80 of the of the
  total error or variance will be caused by 20 of
  the variables. These are the vital few, while
  the remaining are the trivial many. The key
  is to identify these vital few.

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Critical-to (CT) Definitions

• Critical-to-Satisfaction (CTS) characteristics
  expression of the customers vital needs.
• Critical-to-Quality (CTQ) characteristics- the
  product, service and/or transactional
  characteristics that significantly influence one
  or more CTS in terms of quality.
• Critical-to-Delivery (CTD) characteristics-
  in terms of delivery.
• Critical-to-Cost (CTC) characteristics-
  in terms of cost.
• Critical-to-Process (CTP) characteristics-
  Process parameters that significantly influence a
  CTQ, CTD, and/or CTC.

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The Leverage Principle

• Not all X variable affect the outcome (Y)
  equally.
• In Six Sigma process
• Identify the variables that exert strong
  influence (Vital Few).
• Then we must focus on controlling these
  variables. Design of Experiments (DOE) is used
  to achieve this objective.

Y X (x1, x2, x3,,xn )
Dependent Independent
Output Input-process
Effect Cause
Symptom Problem
Monitor Control
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The Leverage Principle(Variation Reduction
Strategies)
Strategy ?1 ?2 ?3 ?4 ?5 ?6 Total Red. Efforts ?Total Impr.
Baseline 4 11 3 2 1 1 -- 12.33
Reduce each by 1 3 10 2 1 0 0 6 10.68 13.4
Eliminate all but one 0 11 0 0 0 0 11 11.00 10.8
Reduce the vital one 4 8 3 2 1 1 3 9.75 20.9
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What does measurement mean?

• Concept of measurement seek to compare or
  contrast a physical attribute of something to a
  rational and invariant standard ? performance
  gap
• Seek to quantify such gaps for purposes of
  communications, verification, and analysis.
• Measure subjective matter (customer satisfaction)
  through surveys, questionnaires
• Measure physical characteristics, time
  characteristics, defect rates.

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How do we know if customers are happy?Goal is to
understand how to better satisfy the customer

• Survey design considerations
• Length (not too long)
• Appearance (simple, not busy)
• Types of questions (statements of fact or
  measures of performance or importance)
• Types of question formats
• Closed-ended (yes/no)
• Rating scales
• Open-ended questions / probes
• Other considerations
• Focus on one theme
• Usually best to include a midpoint in rating
  scales (i.e. odd number)
• Try to solicit feelings toward your competitors.
• Identify specific target control groups
• At least 10 of customer base
• Stratify various customer segments
• Give prior notice, before delivering survey
• Personalize the survey and cover letter
• Address confidentiality
• Offer an incentive or token of appreciation for
  completion

• Follow up with a friendly collection strategy
• Develop action plans that are based on results
• Communicate results to customers
• Follow up with repeat surveys to monitor changes
  over time

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Likert scale

• A subjective scoring system that allows a person
  being surveyed to quantify likes and preferences
  on a 5-point scale, with 1 being the least
  important, relevant, interesting, or other, and 5
  being most excellent, important, etc
• Strongly Agree / Agree / Undecided / Disagree /
  Strongly Disagree
• Very Frequently /Frequently /Occasionally /Rarely
  /Very Rarely /Never
• Very Important / Important / Moderately Important
  / Of Little Importance / Unimportant
• Excellent / Above Average / Average / Below
  Average /Extremely Poor
• Almost Always True / Usually True / Often True /
  Occasionally True / Sometimes But Infrequently
  True / Usually Not True / Almost Never True

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Continuous Scales

• If the data are nonlinear (i.e., with a very wide
  range of values), then a logarithmic scale (in
  this case base 10) may be more appropriate.

• Linear Scale A scale with equal divisions for
  equal values

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Analytical Tool Cause-Effect (CE) Analysis

• CE diagram (fishbone diagram) uses collective
  knowledge to identify the main causes (x) of the
  effect (y) under study.
• Manufacturing diagrams (Six Ms measurement,
  manpower, machines, materials, methods, and
  mother nature).
• Transactional diagrams (4 Ps Policies,
  procedures, personnel, environment).
• Graphical way to show relationships between
  inputs and outputs.
• Label each cause with a C (fixed variable), N
  (Noise) or X (experimental independent
  variable.)
• CE Diagrams can be constructed using MINITAB
  (page 156-157)

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Cause-Effect (CE) Analysis
www.syncfusion.com/.../img/Fishbone_larger.png
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Analytical Tool Failure Mode Effects Analysis
(FMEA)

• Used to assess risks from potential product ,
  service, transaction or process failure modes.
• Widely used in the Analyze and Improve phase, can
  also be used in Control phase.
• Helpful to assist in
• Improving or designing more robust products,
  services processes
• Designing safer products and processes
• Designing safer delivery systems
• Receiving fewer complaints and reducing the
  organizations guarantee costs
• Creating fewer problems or minimizing them in
  everyday business processes
• Provide improvement teams with prioritized causes
  and identifying which causes need to be
  eliminated urgently.

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How does FMEA work?

• Focus on Severity, Occurrence and Detectability
  of each process. Then calculate the the Risk
  Priority number (RPN)
• Each organization can define their own scale
  (1-10, 1-5 )as long as they are consistent
  across the organization.
• Example of FMEA analysis for Auto manufacturer
• Start with a grid to define the potential failures

Product or Process Failure Mode Failure Effects SEV Causes OCC Controls DET RPN Actions Plans PS PO PD PRPN
Engine Overheat Engine Damage                        
Battery Doesn't retain charge Car doesn't start                        
Brakes Brake failure Can't STOP car                        
                             
                             
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FMEASeverity, Occurrence Detectability
Rating Criteria
1 Is not noticed by anybody, has no effect
2 Is not noticed, has only an insignificant effect
3 Causes only small irritations
4 Modest loss of performance
5 Fall in performance level consequence is customer's complaints
6 Fall in performance level that disturbs the capacity to function
7 Disturbed capacity function that leads to an increase in customer dissatisfaction
8 Product or service becomes useless
9 Product or service is illegal
10 Customer or employee is injured or killed.
SEVERITY
Product or Process Failure Mode Failure Effects SEV Causes OCC Controls DET RPN Actions Plans PS PO PD PRPN
Engine Overheat Engine Damage                        
Battery Doesn't retain charge Car doesn't start                        
Brakes Brake failure Can't STOP car                        
                             
                             
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FMEASeverity, Occurrence Detectability
Rating Criteria Probability
1 Once every 6-100 yrs lt2/1,000,000,000
2 Once every 3-6 yrs lt3/10,000,000
3 Once every 1-3 yrs lt6/1,000,000
4 Once a year lt6/100,000
5 Once every 6 months lt1/10,000
6 Once every 3 months lt0.33
7 Once a month lt1
8 Once a week lt5
9 Every 3 to 4 days lt30
10 More than once a day gt30
OCCURANCE
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FMEASeverity, Occurrence Detectability
PROBABILITY OF DETECTION
Rating Criteria
1 The cause of the failure is obvious and can be hindered simply
2 All units are to be inspected automatically
3 Statistical process controls with a systematic failure cause test and corresponding Actions
4 Statistical process controls are to be conducted with a systematic failure cause test.
5 Statistical process controls are to be conducted
6 All units are to be inspected manually and avoidance actions installed
7 All units are to be inspected manually
8 Manual inspections are to be conducted frequently
9 Manual inspections are to be conducted occasionally.
10 The defect caused by the failure is not detectable

• Risk Priority number (RPN) is calculated by
  multiplying
• Severity x Occurrence x Detectabillity

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Analytical Tool XY Matrix

• XY matrix allows everyone involved with a process
  to agree on output (ys) critical to the survey,
  transaction and/or customer.
• Matrix allows the team to assign the level of
  importance of each variable (x) to the output
  (y).
• EXAMPLE of XY matrix as relates to a coffee
  house.
• If the results/ranking were generated during a
  brainstorm session than they should be verified
  based on actual data.

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Graphical Tool Pareto Charts

• Pareto charts help identify the top factors
  (vital few)
• Order X in descending order.
• Add a line showing cumulative of total.
• Based on this which inputs would you focus on to
  insure customer satisfaction?

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Graphical Tool Histogram with Normal Curve
university-software.com/NormalHist.jpg
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Graphical Tool Histogram with Normal Curve
Minitab Calc Random Data Integer Stat Basic
Statistics Graphical Summary
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Graphical Tool Boxplot

• Minimum
• Maximum
• Median
• First Quartile
• Third Quartile

• Minitab
• Stat
• Basic Statistics
• Display Descriptive..
• Boxplot

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Graphical Tool Probability Plot

• Minitab
• Graph
• Probability Plot
• Single

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Graphical Tool Main-Effects Plot

• Main-effects plot graphically compares the level
  of a process output variable at various states of
  process factors
• Lines with steeper slopes have larger impact on
  the output compared to those lines with little or
  no slope
• Used to present result from analysis of variance
  (ANOVA)
• Use to examine the level means for each factor,
  compare the level means for several factors and
  compare the relative strength of the effects
  across factors

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Graphical Tool Main-Effects Plot

• MINITAB
• STAT
• ANOVA
• Main Effect Plot

Input Output
X1 0 60
  1 83
X2 0 72
1 71
X3 0 74
  1 69
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Graphical Tool Run Chart

• A line graph of data points plotted in
  chronological order that helps detect special
  causes of variation
• Understand process variation
• Analyze data for patterns
• Monitor process performance
• Communicate process performance

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Graphical Tool Run Chart
www.pqsystems.com/.../chart_BasicRunChart.png
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Graphical Tool Time-Series Plot

• A time series plot is a graph showing a set of
  observations taken at different points in time
  and charted in a time series.
• Outliers values that do not appear to be
  consistent with the rest of the data
• Discontinuities a break or gap in a process that
  would normally be continuous
• Trends a general tendency in movement or
  direction
• Periodicities any recurrence at regular intervals

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Graphical Tool Time-Series Plot
cookbooks.opengrads.org/images/3/3b/Precip_ti..
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Graphical Tool Multi-Vari Charts

• Show patterns of variation from several possible
  causes on a single chart, or set of charts
• Obtains a first look at the process stability
  over time. Can be constructed in various ways to
  get the best view.
• Positional variation within a part or process
• Cyclical variation between consecutive parts or
  process steps
• Temporal Time variability

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Graphical Tool Multi-Vari Charts
Cus. Size Product Cus. Type Satis.
1 1 2 3.54
2 1 3 3.16
1 2 2 2.42
2 2 2 2.70
1 1 3 3.31
2 1 2 4.12
2 2 1 3.24
2 2 2 4.47
2 1 2 3.83
1 1 1 2.94
Cus. Size 1 small 2 large Product 1
Consumer 2 Manuf. Cus. Type 1 Govt 2
Commercial 3 Education
http//www.qimacros.com/qiwizard/multivari-chart.h
tml
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Graphical Tool Multi-Vari Charts
Minitab Stat Quality Tools Multi Vari Chart
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Graphical Tool Scatter Plot

• Show patterns of variation from several possible
  causes on a single chart, or set of charts
• Obtains a first look at the process stability
  over time. Can be constructed in various ways to
  get the best view.
• Positional variation within a part or process
• Cyclical variation between consecutive parts or
  process steps
• Temporal Time variability

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Graphical Tool Scatter Plot
http//mste.illinois.edu/courses/ci330ms/youtsey/s
catterinfo.html
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Graphical Tool Scatter Plot
http//mste.illinois.edu/courses/ci330ms/youtsey/s
catterinfo.html
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Graphical Tool Scatter Plot
http//mste.illinois.edu/courses/ci330ms/youtsey/s
catterinfo.html
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Graphical Tool Scatter Plot
http//mste.illinois.edu/courses/ci330ms/youtsey/s
catterinfo.html
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Graphical Tools for Process Rep.Process
Flowcharts

• Visual representation of the major process steps.
• Useful to compare as is with should be
  process.
• Determine the limits of the process. Clearly
  define where it begins ends.
• Determine the steps in the process
• Put the steps into sequence
• Draw the flow using standard symbols. Add arrows
  to show flow direction.
• Verify the flow is complete. Is every feedback
  loop complete?
• Standard symbols

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Graphical Tools for Process Rep.Process
Flowcharts
www.breezetree.com/.../8D-process-flowchart.png
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Graphical Tools for Process Rep.Process Mapping

• Process mapping is a workflow diagram to bring
  forth a clearer understanding of a process or
  series of parallel processes
• Cross-Functional Mapping
• As-is vs. To-be

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Graphical Tools for Process Rep.Process Mapping
www.oregon.gov/.../images/iGrafx_Process_Map.JPG
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Graphical Tools for Process Rep. SIPOC Diagram

• Supplier-Input-Process-Output-Customer diagram.
• A high-level picture of the process that depicts
  how the given process is servicing the customer.
  
• Useful to discover customer pain points
• Identify key Ys an Xs with project team.

Suppliers Inputs Process Outputs Customers
Machine manufacturer Bean supplier Filter supplier Cup supplier Coffee beans Water Filter Cup Brewing machine Insert simple flow-chart here Coffee Espresso Repeat (daily) New
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Graphical Tools for Process Rep. SIPOC Diagram
http//www.ptm-consulting.it/immagini/sipoc.jpg
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Graphical Tools for Process Rep. IPO Diagram

• Input-Process-Output diagram is another visual
  rep. of a process activity. Based on the
  transfer equation yf(x)

SOPs Supply Chain
x1Forecast x2Buyer X3 AVL x4BOM x5LT x6Ma
rket Dollar Value
Unforecast demand
Environment AVL
Accuracy
Shipping from Supplier
Noise Variables(N)
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Graphical Tools for Process Rep. SIPOC Diagram
http//www.variancereduction.com/newsletters/image
s/9.6.16.jpg
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Other ToolsForce-Field Analysis

• Force-Field Analysis was developed by Lewin
  (1951) and is widely used to inform
  decision-making, particularly in planning and
  implementing change management programs in
  organizations.
• It is a powerful method for gaining a
  comprehensive overview of the different forces
  acting on a potential policy issue, and for
  assessing their source and strength.

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Force-Field Analysis
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Other ToolsMatrix Analysis

• Technique for finding new combinations of
  products or services.
• List the attributes of the product, service or
  strategy
• Draw up a table using these attributes as column
  headings
• Write down as many variations of the attribute as
  possible within these columns.
• Select one entry from each column. By mixing one
  item from each column, you will create a new
  mixture of components. This is a new product,
  service or strategy.
• Finally, evaluate and improve that mixture to see
  if you can imagine a profitable market for it.

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Other ToolsMatrix Analysis
http//www.mindtools.com/pages/article/newCT_03.ht
m
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Other ToolsChecksheets

• A check sheet is a structured, prepared form for
  collecting and analyzing data
• Decide what event or problem will be observed.
  Develop operational definitions.
• Decide when data will be collected and for how
  long.
• Design the form. Set it up so that data can be
  recorded simply by making check marks or Xs or
  similar symbols and so that data do not have to
  be recopied for analysis.
• Label all spaces on the form.
• Test the check sheet for a short trial period to
  be sure it collects the appropriate data and is
  easy to use.
• Each time the targeted event or problem occurs,
  record data on the check sheet.

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Other ToolsChecksheets
http//www.asq.org/learn-about-quality/data-collec
tion-analysis-tools/overview/check-sheet.html
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Other ToolsScorecards

• A balanced scorecard is a central list of
  numbers, which show each key part of an
  organization's success, such as financials,
  people, operations, suppliers, customers, and
  support systems.
• The numbers should measure not just important
  outcomes, but also the factors which influence,
  or drive, those outcomes.

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Other ToolsScorecards
www.jiscinfonet.ac.uk/.../scorecard
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Other ToolsAffinity Diagram

• The affinity diagram organizes a large number of
  ideas into their natural relationships
• Record each idea with a marking pen on a separate
  sticky note or card. Randomly spread notes on a
  large work surface so all notes are visible to
  everyone.
• Look for ideas that seem to be related in some
  way. Place them side by side. Repeat until all
  notes are grouped.
• Participants can discuss the shape of the chart,
  any surprising patterns, and especially reasons
  for moving controversial notes. When ideas are
  grouped, select a heading for each group.
• Combine groups into supergroups if appropriate.

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Other ToolsAffinity Diagram
http//www.asq.org/learn-about-quality/idea-creati
on-tools/overview/affinity.html
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Affinity Diagram
http//www.asq.org/learn-about-quality/idea-creati
on-tools/overview/affinity.html