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Session 10: Cause and Effect




                                    Idea Diagrams:
                                    Cause and Effect, Affinity and
                                    Tree Diagrams




                                                                      1




                                    Seven Basic Quality Tools
                               1.    Process Mapping / Flow Charts*
                               2.    Check Sheets
                               3.    Pareto Analysis
                               4.    Cause & Effect Diagrams
                               5.    Histograms
                               6.    Scatter Diagrams (XY Graph)
                               7.    Control Charts



                                                                      2




                                                                          1
Six Sigma Greenbelt: University of Michigan
Session 10: Cause and Effect




                                   Topics
                           I.     Cause and Effect Diagrams
                                    A.   Ishikawa Fishbone Diagram
                                    B.   Failure Mode Cause and Effect Diagram

                           II.    Affinity Diagram
                           III.   Tree Diagram




                                                                                           3




                                    I. Cause-and-Effect Diagrams

                                  Cause-and-Effect Diagrams are used to:
                                         visually identify potential causes of problems.
                                         organize cause-and-effect relationships.
                                         assist in root cause analysis.
                                         demonstrate knowledge of problem-solving team.


                                  Two Common Formats:
                                   A.    Ishikawa (Fishbone) Diagram
                                   B.    Failure Mode Cause-and-Effect Diagram




                                                                                           4




                                                                                               2
Six Sigma Greenbelt: University of Michigan
Session 10: Cause and Effect




                                  A. Cause & Effect Diagram
                                  (Ishikawa or Fishbone Diagram)



                          Cause Branch                           Effect  failure
                                    twig                         Branch  Main Categories
                                                                  (Example: 4Ms - man, method,
                                           twiglet
                                                                  machine, material)
                                                        Effect
                                                                 Twig  1st Level Causes
                                                                 Twiglets  2nd Level Causes

                                              causes       effect

                                                                                            5




                                 Cause-and-Effect Diagrams
                             Classification headings in cause-and-effect diagrams often
                             are derived from qualitative process analysis.
                             4Ms (5 or 6 Ms)
                                 Man (personnel), Method, Machine, Material
                                 Measurement system (or, include with machine)
                                 Mother nature  uncontrollable external issues




                                                                                            6




                                                                                                  3
Six Sigma Greenbelt: University of Michigan
Session 10: Cause and Effect




                                   Cause and Effect Analysis

                              Construct the cause and effect diagram as the
                              basis of analysis.
                              Do not stop until you reach root causes (not
                              symptoms).
                              Ask questions and question assumptions.
                              Do not jump to The Solution.




                                                                                    7




                                   Constructing a Cause and
                                   Effect Diagram

                              Decide the problem to be analyzed.
                              Draw and label the effect line.
                              Draw and label the cause branches (e.g., 4Ms).
                              Ask why problem occurs to determine first level
                              causes
                              Continue to determine the next level of causes. Try
                              not to stop until you reach root causes (vs.
                              symptoms).
                              Highlight likely root causes.



                                                                                    8




                                                                                        4
Six Sigma Greenbelt: University of Michigan
Session 10: Cause and Effect



                                   Creating a Cause and Effect
                                   Diagram




                                                                       Effect



                                                              Effect - failure

                                                                                  9




                                   Elements of a Cause and Effect
                                   Diagram

                                      Man       Method




                                                                       Effect

                                                          Branch - broad
                                                          categories,
                                                          i.e. 4 Ms
                                     Machine   Material
                                                                                 10




                                                                                      5
Six Sigma Greenbelt: University of Michigan
Session 10: Cause and Effect




                                Elements of a Cause and Effect
                                Diagram
                                      Man       Method
                                                            1st Level Cause



                                                                      Effect



                                                          Twig - 1st Level Cause
                                     Machine   Material
                                                                               11




                                Elements of a Cause and Effect
                                Diagram
                                      Man       Method


                                                           2nd Level Cause

                                                                      Effect




                                     Machine   Material
                                                                               12




                                                                                    6
Six Sigma Greenbelt: University of Michigan
Session 10: Cause and Effect



                                   Lecture Exercise: Create a
                                   Cause and Effect Diagram
                                Create a Cause and Effect Diagram for the
                                following problem:
                                    Effect: customer dissatisfaction for delayed airline
                                    flight departures


                                Use the following Cause Branches:
                                    Machine (Equipment); Man (Personnel); Method;
                                    Materials; Environment



                                                                                           13




                                   Lecture Exercise: Machine

                              Machine         Gate
                                              not
                          Mechanical          working



                                                                                 Flight
                                                                                 Delays




                                                                                           14




                                                                                                7
Six Sigma Greenbelt: University of Michigan
Session 10: Cause and Effect




                                   Lecture Exercise: Man
                                Machine       Gate          Man
                                              not                     Late
                          Mechanical          working                 Crew

                                                         Late          Cleaning
                                                         Pilot         Late
                                                                                  Flight
                                                                                  Delays




                                                                                           15




                                   Lecture Exercise: Method
                                Machine       Gate          Man
                                              not                     Late
                          Mechanical          working                 Crew

                                                         Late          Cleaning
                                                         Pilot         Late
                                                                                  Flight
                                                                                  Delays


                                                                     Gate
                                                        Boarding
                                                                     blocked
                                                        Process
                                                                         Unclear
                                                                         Procedure
                                                            Method
                                                                                           16




                                                                                                8
Six Sigma Greenbelt: University of Michigan
Session 10: Cause and Effect




                                     Lecture Exercise: Materials
                                Machine       Gate          Man
                                              not                     Late
                          Mechanical          working                 Crew

                                                         Late          Cleaning
                                                         Pilot         Late
                                                                                  Flight
                                                                                  Delays
                                                        Late
                                   Late                 Meals
                                   Baggage                           Gate
                                                        Boarding
                                                                     blocked
                                                        Process
                                                                         Unclear
                                                 Late                    Procedure
                            Materials                       Method
                                                 Fuel
                                                                                           17




                                     Lecture Exercise: Environment

                                Machine       Gate          Man
                                              not                     Late
                          Mechanical          working                 Crew

                                                         Late          Cleaning
                         Environment                     Pilot         Late
                         Weather     FAA Delay                                    Flight
                                                                                  Delays
                                                        Late
                                   Late                 Meals
                                   Baggage                           Gate
                                                        Boarding
                                                                     blocked
                                                        Process
                                                                         Unclear
                                                 Late                    Procedure
                              Materials                     Method
                                                 Fuel
                                                                                           18




                                                                                                9
Six Sigma Greenbelt: University of Michigan
Session 10: Cause and Effect




                                     B. Failure Mode Cause-and-Effect
                                     Diagram
                                         Methods

                                                                           Note: may have multiple effects,
                          Machinery                                        and/or multiple causes


                                                                        Downstream                End-user
                          Material                   Failure              Process                 Operation
                                                     Mode


                          Man (Person)


                                            Environment



                                            Causes              |||                     Effects                   19




                                     Failure Mode Cause-and-Effect
                                     Diagram (Airline Example)
                                         Man
                                         Late Crew


                          Method
                          Boarding
                          Process
                                                     Failure
                          Equipment                  Mode               Customer              Missing         Lost
                                                                      Dissatisfaction       Connections       Profits
                            Gate Not
                            Working

                          Material
                          Late Fuel                            Flight Does Not Leave On-Time
                          Late Baggage
                                            Environment
                                            Severe Weather


                                            Causes              |||                     Effects                   20




                                                                                                                        10
Six Sigma Greenbelt: University of Michigan
Session 10: Cause and Effect




                                   II. Affinity Diagram

                                Affinity  natural attraction
                                Brainstorming technique used to gather and group
                                ideas.
                                Useful for analyzing causes of quality problems, survey
                                analysis, customer complaints.
                                Basic premise 
                                   while numerous reasons may exist for a problem, they are
                                   usually grouped around some common themes. And, by
                                   identifying these common themes, a team can better focus on
                                   finding root causes and implementing multilateral
                                   recommendations.


                                                                                               21




                                   Constructing Affinity Diagrams
                                   for Six Sigma Projects

                                Basic Steps:
                                   Select a problem.
                                   Identify causes via brainstorming or interviews.
                                   Write each cause on a note card or Post-It (each cause should
                                   be 2-7 words)
                                   Examine causes and cluster them into groups (usually in
                                   silence).
                                   Review the clusters and decide on best grouping.
                                   Use final grouping to generate additional causes.
                                   Develop a plan to address major groupings or potential root
                                   causes.



                                                                                               22




                                                                                                    11
Six Sigma Greenbelt: University of Michigan
Session 10: Cause and Effect



                                      Example: Software Re-Design
                                      Project

                             Six Sigma Project
                                Problem: employees are complaining about the limitations of an
                                internally developed excel-based program used in the Production
                                Part Approval Process.
                                    Software Product  provides a statistical summary of the part
                                    characteristics to verify production readiness.
                                Six Sigma Team was formed to identify causes of the complaints.
                                Team interviewed various users for input. Can you think of any
                                likely concerns based on past experience?




                                                                                                 23




                                Exercise: Affinity Diagram
                                (create 2-4 groupings of concerns)
                                1.    Difficult to navigate
                                2.    No standardized summary reports
                                3.    Limited graphical summary reports
                                4.    Cannot analyze multiple characteristics
                                5.    Difficult to change part specifications
                                6.    Cannot handle blank cells within data range
                                7.    Few user friendly features
                                8.    Difficult to import/export data
                                9.    No formula protection
                                10.   No outlier analysis
                                11.   Takes too long to setup print feature
                                12.   Data Files too big (programming in every file)
                                13.   Too much manual input
                                14.   No customized features to perform analysis
                                15.   No customized naming of files


                                                                                                 24




                                                                                                      12
Six Sigma Greenbelt: University of Michigan
Session 10: Cause and Effect




                                       Groupings

                               Suppose the team has identified 3 Groupings for the
                               concerns.
                               Place the previous concerns into the following:

                                 A.   Data Analysis Capability

                                 B.   Functionality  Ease of Use

                                 C.   Programming Efficiency


                                                                                                              25




                                      Affinity Diagram 
                                      Production Part Approval Software
                                      A. Data Analysis Capability
                                                                               B. Functionality  Ease of Use
                          Limited graphical summary reports
                                                                            Difficult to navigate
                          Cannot analyze multiple characteristics
                                                                            Few user friendly features
                          Difficult to change part specifications
                                                                            Takes too long to setup print feature
                          No standardized summary reports
                                                                            Too much manual input
                          No outlier analysis
                                                                            No customized naming of files
                          No customized features to perform analysis
                                                 C. Programming Efficiency
                                          Cannot handle blank cells within data range
                                          Difficult to import/export data
                                          No formula protection
                                          Data Files too big (programming in every file)
                                                                                                              26




                                                                                                                    13
Six Sigma Greenbelt: University of Michigan
Session 10: Cause and Effect




                                   Affinity Diagram  Next Steps

                             After grouping all of the data, you should brainstorm for
                             additional causes / concerns. (Grouping  generate
                             more ideas)

                             Case Study 
                                 For this case study, a list of recommendations were developed to
                                 improve the software tool including converting the tool into a read-
                                 only application.




                                                                                                  27




                                 III. Tree Diagram
                                A tree diagram provides a hierarchy of cause-effect
                                relationships.
                                Often need to keep asking why to better understand
                                root cause(s) of problems.
                                                                         Cause
                                                                                         
                                                     Cause
                                                                         Cause
                               Problem
                                                                         Cause           


                                                     Cause               Cause

                                                                         .
                                WHY?                                                              28




                                                                                                        14
Six Sigma Greenbelt: University of Michigan
Session 10: Cause and Effect




                                Tree Diagram Example:
                                Loan Case Study                                                    Why?
                             Loan takes too long     Internal processing errors   Loan application
                             errors from customer     Loan officers do not know all the details to
                             obtain for a lending program     Branch Managers do not provide
                             standard guidelines of lender programs      Central office does not
                             provide branch managers with support to develop standards.


                                                                                Loan Application
                                                       Internal                 Errors
                                                      Processing
                                                        Errors
                            Loan take                                           Lender Program changes

                            Too long
                                                                                Loan Application Errors
                            To process
                                                      Underwriting              Delays waiting for external
                                                        Delays                  Underwriter to process loan

                                                                                  .                  29




                                   Tree Diagram  Alternative Use
                                Tree Diagrams also may be used in the IMPROVE
                                PHASE to identify ways or means to complete a task
                                or objective.

                                                                           Means
                                                                                             
                                                      Means
                                                                           Means
                              Objective
                                                                           Means             


                                                      Means                Means

                                                                           .
                                How?
                                                                                                      30




                                                                                                              15
Six Sigma Greenbelt: University of Michigan

More Related Content

10t causeeffect-2

  • 1. Session 10: Cause and Effect Idea Diagrams: Cause and Effect, Affinity and Tree Diagrams 1 Seven Basic Quality Tools 1. Process Mapping / Flow Charts* 2. Check Sheets 3. Pareto Analysis 4. Cause & Effect Diagrams 5. Histograms 6. Scatter Diagrams (XY Graph) 7. Control Charts 2 1 Six Sigma Greenbelt: University of Michigan
  • 2. Session 10: Cause and Effect Topics I. Cause and Effect Diagrams A. Ishikawa Fishbone Diagram B. Failure Mode Cause and Effect Diagram II. Affinity Diagram III. Tree Diagram 3 I. Cause-and-Effect Diagrams Cause-and-Effect Diagrams are used to: visually identify potential causes of problems. organize cause-and-effect relationships. assist in root cause analysis. demonstrate knowledge of problem-solving team. Two Common Formats: A. Ishikawa (Fishbone) Diagram B. Failure Mode Cause-and-Effect Diagram 4 2 Six Sigma Greenbelt: University of Michigan
  • 3. Session 10: Cause and Effect A. Cause & Effect Diagram (Ishikawa or Fishbone Diagram) Cause Branch Effect failure twig Branch Main Categories (Example: 4Ms - man, method, twiglet machine, material) Effect Twig 1st Level Causes Twiglets 2nd Level Causes causes effect 5 Cause-and-Effect Diagrams Classification headings in cause-and-effect diagrams often are derived from qualitative process analysis. 4Ms (5 or 6 Ms) Man (personnel), Method, Machine, Material Measurement system (or, include with machine) Mother nature uncontrollable external issues 6 3 Six Sigma Greenbelt: University of Michigan
  • 4. Session 10: Cause and Effect Cause and Effect Analysis Construct the cause and effect diagram as the basis of analysis. Do not stop until you reach root causes (not symptoms). Ask questions and question assumptions. Do not jump to The Solution. 7 Constructing a Cause and Effect Diagram Decide the problem to be analyzed. Draw and label the effect line. Draw and label the cause branches (e.g., 4Ms). Ask why problem occurs to determine first level causes Continue to determine the next level of causes. Try not to stop until you reach root causes (vs. symptoms). Highlight likely root causes. 8 4 Six Sigma Greenbelt: University of Michigan
  • 5. Session 10: Cause and Effect Creating a Cause and Effect Diagram Effect Effect - failure 9 Elements of a Cause and Effect Diagram Man Method Effect Branch - broad categories, i.e. 4 Ms Machine Material 10 5 Six Sigma Greenbelt: University of Michigan
  • 6. Session 10: Cause and Effect Elements of a Cause and Effect Diagram Man Method 1st Level Cause Effect Twig - 1st Level Cause Machine Material 11 Elements of a Cause and Effect Diagram Man Method 2nd Level Cause Effect Machine Material 12 6 Six Sigma Greenbelt: University of Michigan
  • 7. Session 10: Cause and Effect Lecture Exercise: Create a Cause and Effect Diagram Create a Cause and Effect Diagram for the following problem: Effect: customer dissatisfaction for delayed airline flight departures Use the following Cause Branches: Machine (Equipment); Man (Personnel); Method; Materials; Environment 13 Lecture Exercise: Machine Machine Gate not Mechanical working Flight Delays 14 7 Six Sigma Greenbelt: University of Michigan
  • 8. Session 10: Cause and Effect Lecture Exercise: Man Machine Gate Man not Late Mechanical working Crew Late Cleaning Pilot Late Flight Delays 15 Lecture Exercise: Method Machine Gate Man not Late Mechanical working Crew Late Cleaning Pilot Late Flight Delays Gate Boarding blocked Process Unclear Procedure Method 16 8 Six Sigma Greenbelt: University of Michigan
  • 9. Session 10: Cause and Effect Lecture Exercise: Materials Machine Gate Man not Late Mechanical working Crew Late Cleaning Pilot Late Flight Delays Late Late Meals Baggage Gate Boarding blocked Process Unclear Late Procedure Materials Method Fuel 17 Lecture Exercise: Environment Machine Gate Man not Late Mechanical working Crew Late Cleaning Environment Pilot Late Weather FAA Delay Flight Delays Late Late Meals Baggage Gate Boarding blocked Process Unclear Late Procedure Materials Method Fuel 18 9 Six Sigma Greenbelt: University of Michigan
  • 10. Session 10: Cause and Effect B. Failure Mode Cause-and-Effect Diagram Methods Note: may have multiple effects, Machinery and/or multiple causes Downstream End-user Material Failure Process Operation Mode Man (Person) Environment Causes ||| Effects 19 Failure Mode Cause-and-Effect Diagram (Airline Example) Man Late Crew Method Boarding Process Failure Equipment Mode Customer Missing Lost Dissatisfaction Connections Profits Gate Not Working Material Late Fuel Flight Does Not Leave On-Time Late Baggage Environment Severe Weather Causes ||| Effects 20 10 Six Sigma Greenbelt: University of Michigan
  • 11. Session 10: Cause and Effect II. Affinity Diagram Affinity natural attraction Brainstorming technique used to gather and group ideas. Useful for analyzing causes of quality problems, survey analysis, customer complaints. Basic premise while numerous reasons may exist for a problem, they are usually grouped around some common themes. And, by identifying these common themes, a team can better focus on finding root causes and implementing multilateral recommendations. 21 Constructing Affinity Diagrams for Six Sigma Projects Basic Steps: Select a problem. Identify causes via brainstorming or interviews. Write each cause on a note card or Post-It (each cause should be 2-7 words) Examine causes and cluster them into groups (usually in silence). Review the clusters and decide on best grouping. Use final grouping to generate additional causes. Develop a plan to address major groupings or potential root causes. 22 11 Six Sigma Greenbelt: University of Michigan
  • 12. Session 10: Cause and Effect Example: Software Re-Design Project Six Sigma Project Problem: employees are complaining about the limitations of an internally developed excel-based program used in the Production Part Approval Process. Software Product provides a statistical summary of the part characteristics to verify production readiness. Six Sigma Team was formed to identify causes of the complaints. Team interviewed various users for input. Can you think of any likely concerns based on past experience? 23 Exercise: Affinity Diagram (create 2-4 groupings of concerns) 1. Difficult to navigate 2. No standardized summary reports 3. Limited graphical summary reports 4. Cannot analyze multiple characteristics 5. Difficult to change part specifications 6. Cannot handle blank cells within data range 7. Few user friendly features 8. Difficult to import/export data 9. No formula protection 10. No outlier analysis 11. Takes too long to setup print feature 12. Data Files too big (programming in every file) 13. Too much manual input 14. No customized features to perform analysis 15. No customized naming of files 24 12 Six Sigma Greenbelt: University of Michigan
  • 13. Session 10: Cause and Effect Groupings Suppose the team has identified 3 Groupings for the concerns. Place the previous concerns into the following: A. Data Analysis Capability B. Functionality Ease of Use C. Programming Efficiency 25 Affinity Diagram Production Part Approval Software A. Data Analysis Capability B. Functionality Ease of Use Limited graphical summary reports Difficult to navigate Cannot analyze multiple characteristics Few user friendly features Difficult to change part specifications Takes too long to setup print feature No standardized summary reports Too much manual input No outlier analysis No customized naming of files No customized features to perform analysis C. Programming Efficiency Cannot handle blank cells within data range Difficult to import/export data No formula protection Data Files too big (programming in every file) 26 13 Six Sigma Greenbelt: University of Michigan
  • 14. Session 10: Cause and Effect Affinity Diagram Next Steps After grouping all of the data, you should brainstorm for additional causes / concerns. (Grouping generate more ideas) Case Study For this case study, a list of recommendations were developed to improve the software tool including converting the tool into a read- only application. 27 III. Tree Diagram A tree diagram provides a hierarchy of cause-effect relationships. Often need to keep asking why to better understand root cause(s) of problems. Cause Cause Cause Problem Cause Cause Cause . WHY? 28 14 Six Sigma Greenbelt: University of Michigan
  • 15. Session 10: Cause and Effect Tree Diagram Example: Loan Case Study Why? Loan takes too long Internal processing errors Loan application errors from customer Loan officers do not know all the details to obtain for a lending program Branch Managers do not provide standard guidelines of lender programs Central office does not provide branch managers with support to develop standards. Loan Application Internal Errors Processing Errors Loan take Lender Program changes Too long Loan Application Errors To process Underwriting Delays waiting for external Delays Underwriter to process loan . 29 Tree Diagram Alternative Use Tree Diagrams also may be used in the IMPROVE PHASE to identify ways or means to complete a task or objective. Means Means Means Objective Means Means Means . How? 30 15 Six Sigma Greenbelt: University of Michigan