Cause and Effect Analysis: 1. Fishbone Diagram 2. Cause and Effect Matrix

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Cause and Effect Cause and Effect Analysis:Analysis:

1. Fishbone Diagram1. Fishbone Diagram2. Cause and Effect Matrix2. Cause and Effect Matrix

2

Cause and Effect Analysis

Learning ObjectivesLearning Objectives Define the relationship between Cause and

Effect

Explain use and construction of: Fishbone Diagram

Guidelines for Brainstorming

Cause and Effect Matrix

Learn how to integrate Fishbone Diagram and Cause & Effect Matrix into your Company SOPs

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What do you mean by “ Cause & Effect”?What do you mean by “ Cause & Effect”?

CAUSEEvents/conditions

that led tothe problem

A PROBLEM WHICHHAS OCCURED

EFFECTSymptoms that

provide evidenceof the problem

A POTENTIALFUTURE PROBLEM

EFFECTSymptoms thatwould result

from the problem

CAUSEEvents/conditionsthat would lead to

the problem

Dave Wessel, “An Ounce of Prevention”, Quality Progress, Dec, 1998

(FMEA)

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Cause - Effect RelationshipCause - Effect Relationship

CAUSEEvents/conditions

that led tothe problem

A PROBLEM WHICHHAS OCCURED

EFFECTSymptoms that

provide evidenceof the problem

ACTION

CO

RR

EC

TIVE

Elim

inates the

CA

US

E

of a problem

AD

AP

TIV

EL

imit

s th

eE

FF

EC

T o

f a

pro

ble

m o

r d

evia

tio

nDave Wessel, “An Ounce of Prevention”, Quality Progress, Dec, 1998

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Fishbone Fishbone DiagramDiagram

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What is a Fishbone Diagram?What is a Fishbone Diagram?A visual tool used to identify, explore and graphically display all the possible causes related to a problem to discover root causes.

A Fishbone diagram is also known as a Cause and Effect Diagram or Ishikawa Diagram.

MethodsMaterials

Machinery Manpower

Problem/Desired

Improvement

C/N/X

C

C

C

N N

NNN

C

C

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Dr Kaoru IshikawaDr Kaoru Ishikawa Quality control statistician Professor in University of Tokyo One of the pioneers of Japan’s quality

revolution in the 1940s Played major role in growth of QC circles Best known for formalizing use of

Cause-and-Effect Diagram Won the Deming Prize and Shewhart

Medal ASQ established the Ishikawa Medal to

recognize the human side of quality

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Why Use Fishbone Diagrams?Why Use Fishbone Diagrams? To discover the most probable causes to a

problem (or effect)– Sometimes, the effect can be a desirable effect.– When something desirable has happened, it is

useful to find out what caused it so that you can make it happen again

To visual possible relationships between causes for a given problem under investigation

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Constructing a Fishbone DiagramConstructing a Fishbone Diagram1. Establish what the problem (effect) is

It must be stated in clear and concise terms, agreed by everyone.

2. Write the effect on the head of the fish3. Decide the major categories of causes

Brainstorming Use standard categories such as 5M+E

(Machines, Materials, Methods, Manpower, Measurement & Environment)

Use major steps in the process if the effect is resulted from a recognizable process • See example????

Let’s create a Fishbone Diagram using MinitabLet’s create a Fishbone Diagram using Minitab

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Constructing a Fishbone DiagramConstructing a Fishbone DiagramStat Quality Tools Cause-and-Effect

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Constructing a Fishbone DiagramConstructing a Fishbone Diagram

Surface Flaws

Man

Machines

Materials

Methods

Measurements

Environment

Fishbone Diagram for Surface Flaws

Major categories of causes (or sometimes call major bones)

Problem (effect)at the “head of the fish”

List specific causes in each category

Why do we need to group the causes?Why do we need to group the causes?

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Constructing a Fishbone DiagramConstructing a Fishbone Diagram4. Identify possible causes through Brainstorming

• Identify specific causes within each major category that may be affecting the problem.

Surface Flaws

Condensation

Moisture%

Inspectors

Microscopes

Micrometers

Brake

Engager

Angle

Suppliers

Lubricants

Alloys

Speed

Lathes

Bits

Sockets

Operators

Training

Supervisors

Shifts

Personnel

Machines

Materials

Methods

Measurements

Environment

Fishbone Diagram for Surface Flaws

3. Continue asking: ‘Why is this happening?’ until you no longer get useful information.

Machine feedrate

Machine rpm

Brand of bit

Size of bit

2. Repeat this procedure with each specific cause to produce sub-causes.

1. The team should ask : ‘What are the machine issues affecting/causing the problem?’

PrecisionAccuracy

Calibration Method

Calibration Interval

When do we know we have reached the root cause ?

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Analyzing a Fishbone DiagramAnalyzing a Fishbone Diagram 5. When brainstorming session is completed, every

cause should be labeled as either a “C”, “N” or “X”.

C variables that must be held as constant as possible and require standard operating procedures to insure consistency

N variables that are noise or uncontrolled variables and cannot be cheaply/easily held constant

X variables considered to be KPIVs and need to be experimented to determine what influence each has on the output and what their optimal settings should be to achieve customer-desired performance

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Analyzing a Fishbone DiagramAnalyzing a Fishbone Diagram6. The team should analyze and zoom in those

“most likely causes”.

Helpful HintLook out for causes that appear in more than one category. They may be the “most likely causes”.

7. The most likely causes should be prioritized for further investigation.

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Example of how fishbone diagram can be used in SCAR.

Received complaint/reject

from customer, in-house or supplier.

Hold meeting with relevant

departments (if necessary)

-receive CAR reply from production- reply to customer

Follow up on CAR

Generate report for

management review

QA personnel verify the defects.

Issue CAR to production.

Purge in-house stock

Fishbone diagram can be used here to brainstorm/ identify root causes

1. Fishbone diagram can be used here to brainstorm/ identify root causes.

2. To prioritize and work on most likely causes.

Section of SCAR Procedure

Integrating Fishbone Diagram into SOPsIntegrating Fishbone Diagram into SOPs

Should also update Fishbone diagram

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5.4.2.4 It is the responsibility of the EA of CMM section to set-up the trend-tests forout-of-control in the "SPC" software.

5.4.2.5 The E.A/Supervisor of the 'CMM' section shall monitor the X-R Charts on thecomputer and look-out for out-of-control situation. When out-of-control is detected, he shall analyse the subgroup data, the histogram and the prevailing Cpk value,based on these he shall decide the action to take. When the situation necessitates, a "PCAR" shall be issued to the Production E.A/Supervisor.

5.4.2.6 The Production Supervisor/E.A shall analyze the problem and take corrective actions on the process concerned, after which, new samples shall be submitted for measurement. When the problem has been rectified, Production Supervisor/EAshall write in the "PCAR" form, the corrective actions taken and return the form to the E.A or Supervisor of "CMM" section.

Example of how fishbone diagram can be used in SPC control

Section of SPC Control Procedure

Fishbone diagram can be used here to brainstorm/ identify root causes

Integrating Fishbone Diagram into SOPsIntegrating Fishbone Diagram into SOPs

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The effort to integrate Fishbone Diagram into SPC and SCAR procedures should be translated into specific tasks in the Work Breakdown Structure.

S/N Tasks Task Owner Target Completion Date

Specific Training needed for Task

Owner/ Date

Core Team Member In

Charge

Internal Verified Date

Group Phase End Date

Group 1 Tools

1 SPC

Integrate Fishbone Diagram in the SPC procedure/system

James 10-Dec-01 Fishbone Diagram -15 Oct 2001

Nick 15-Dec-01 31-Dec-01

2 SCAR

Integrate Fishbone Diagram in the SCAR procedure/system

Harry 10-Dec-01 Fishbone Diagram - 15 Oct 2001


Link Tools Integration Tasks to Work Link Tools Integration Tasks to Work Breakdown StructureBreakdown Structure

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Cause & Effect Cause & Effect MatrixMatrix

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Cause and Effect MatrixCause and Effect Matrix

Rating of Importance to

Customer

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

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Req

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Total

Process Step Process Input

1 02 03 04 05 06 07 08 09 010 011 012 013 014 015 016 017 018 019 020 0

0

Total 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Lower Spec

Target

Upper Spec


Rating of Importance to

Customer

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

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Total

Process Step Process Input

1 02 03 04 05 06 07 08 09 010 011 012 013 014 015 016 017 018 019 020 0

0

Total 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Lower Spec

Target

Upper Spec


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Description: Cause and Effects MatrixDescription: Cause and Effects Matrix Simple QFD (Quality Function Deployment) matrix. Used to relate and prioritize X’s to customer Y’s through

numerical ranking using the process map as the primary source.

Y’s are scored as importance to the customer X’s are scored as to relationship to outputs

This is the team’s first stab at determining Y = f(X)

ResultsResults Pareto of Key Inputs to evaluate in the FMEA and Control Plans Input into the Capability Study Input into the initial evaluation of the Process Control Plan

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Constructing a Cause & Effect MatrixConstructing a Cause & Effect Matrix1. List key outputs (Y’s)

Rating of Importance to Customer

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Process Inputs Gel T

ime

Vis

cosity

Cle

anlin

ess

Colo

r

Hom

ogeneity

Consis

tency

Tem

pera

ture

Solid

s

Total

1 02 03 04 05 06 07 0


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2. Rank Y’s with respect to customer importance


9 9 7 10 10 9 3 2 6

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Process Inputs Gel

Tim

e

Vis

cosi

ty

Cle

anlin

ess

Col

or

Hom

ogen

eity

Con

sist

ency

Dig

ets

Tim

e

Tem

pera

ture

Sol

ids

Total

1 02 03 04 05 06 07 08 0


Constructing a Cause & Effect MatrixConstructing a Cause & Effect Matrix

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3. List key inputs (X’s)


9 9 7 10 10 9 3 2 6

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Process Inputs Gel Tim

e

Vis

cosity

Cle

anlin

ess

Colo

r

Hom

ogeneity

Consis

tency

Dig

ets

Tim

e

Tem

pera

ture

Solid

s

Total

1Scales Accuracy

0

2Preheating DICY TK

0

3DMF Load Accuracy

0

4DMF Cleanliness

0

5DMF Raw Materials

0

6DICY Load Accuracy

0

7DICY Envir. Factors

0

8DICY Raw Materials

0

9DICY Mixer Speecd

0

Input Variables


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You are ready to correlate customer requirements to the process input variables

Avoid confusion and inconsistency by establishing scoring criteria:

0 = no correlation1 = the process effect only remotely affects the customer

requirement4 = The input variable has a moderate effect on the

customer requirement9 = The input variable has a direct and strong effect on the

customer requirements


Note: Not recommended to use more than 5 different criteria.

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4. Relate X’s to Y’sRating of Importance to Customer

9 9 9 10 10 9 2 2 6

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15


e

Vis

cosity

Cle

anliness

Colo

r

Hom

ogeneity

Consis

tency

Dig

ets

Tim

e

Tem

pera

ture

Solids

Total

1Scales Accuracy

9 9 3 1 1 9 1 1 9 348

2Preheating DICY TK

1 1 1 1 1 1 1 1 1 66

3DMF Load Accuracy

3 9 1 1 1 9 1 3 9 255

4DMF Cleanliness

1 1 5 1 1 1 1 1 1 102

5DMF Raw Materials

1 1 1 1 1 1 1 1 1 66

6DICY Load Accuracy

9 9 1 1 1 9 1 1 1 282


9 5 3 1 1 9 1 1 1 247

8DICY Raw Materials

8 5 1 1 1 9 1 1 2 242

9DICY Mixer Speecd

1 1 1 1 7 1 1 1 1 126

Y’s


X’s

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9 9 9 10 10 9 2 2 6

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15


e

Vis

cosity

Cle

anliness

Colo

r

Hom

ogeneity

Consis

tency

Dig

ets

Tim

e

Tem

pera

ture

Solids

Total

1Scales Accuracy

9 9 3 1 1 9 1 1 9 348

2Preheating DICY TK

1 1 1 1 1 1 1 1 1 66

3DMF Load Accuracy

3 9 1 1 1 9 1 3 9 255

4DMF Cleanliness

1 1 5 1 1 1 1 1 1 102

5DMF Raw Materials

1 1 1 1 1 1 1 1 1 66

6DICY Load Accuracy

9 9 1 1 1 9 1 1 1 282


9 5 3 1 1 9 1 1 1 247

8DICY Raw Materials

8 5 1 1 1 9 1 1 2 242

9DICY Mixer Speecd

1 1 1 1 7 1 1 1 1 126

5. Cross-multiply and add

Key inputs are now ranked in importance with respect to the key outputs


So??

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9 9 7 10 10 9 3 2 6

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Process Inputs Gel

Tim

e

Vis

cosi

ty

Cle

anlin

ess

Col

or

Hom

ogen

eity

Con

sist

ency

Dig

ets

Tim

e

Tem

pera

ture

Sol

ids

Total

1Scales Accuracy

9 8 2 1 1 9 1 1 8 321

2Preheating DICY TK

1 1 1 1 1 1 1 1 1 65

3DMF Load Accuracy

3 8 1 1 1 8 1 3 8 255

4DMF Cleanliness

1 1 4 2 1 2 1 1 1 105

5DMF Raw Materials

1 1 1 1 1 2 1 1 1 74

6DICY Load Accuracy

9 7 1 1 1 9 1 1 2 269


8 5 3 1 1 8 1 1 2 247

8DICY Raw Materials

8 5 1 1 1 9 1 1 2 242

9DICY Mixer Speecd

1 1 1 1 7 1 1 1 1 125

C&E Matrix

FMEA

Process or Product Name:

Prepared by:

Responsible: FMEA Date (Orig) ______________ (Rev) _____________

Process Step/Part Number Potential Failure Mode Potential Failure Effects

SEV Potential Causes

OCC Current Controls

DET

RPN

Spin Draw Process

Fiber Breakouts Undersized package, High SD panel-hours lost 2

Dirty Spinneret8

Visual Detection of Wraps and broken Filaments 9 144

5Filament motion

2Visual Sight-glass

8 80

8Polymer defects

2Fuzzball Light

9 144

0

Process/Product Failure Modes and Effects Analysis

(FMEA)

Capability Summary

Custom er Requirem ent (Output Variable)

M easurem ent Technique

% R&R or P/T Ratio

Upper Spec Lim it

TargetLower Spec Lim it

Cp CpkSam ple

SizeDate Actions

Gel Tim eViscosityCleanlinessColorHom ogeneityConsistencyDigets Tim eTem peratureSolids

Key Process Output VariableCapability Status Sheet

The Key Outputs are evaluated ability to meet

customer spec.

Control Plan Summary

Product: Core Team: Date (Orig):Key Contact:Phone: Date (Rev):

Process Process Step Input OutputProcess

Specification (LSL, USL, Target)

Cpk /Date Measurement

Technique%R&R

P/TSample

SizeSample

FrequencyControl Method

Reaction Plan

DICY Turn Steam on Scales Accuracy

DMF Load DMF DMF Load Accuracy

DMF Load DMF DMF Cleanliness

DICY Load DICY DICY Envir. Factors

DICY Load DICY DICY Load Accuracy

DICY Load DICY DICY Raw Materials

DICY Load DICY DICY Mixer Speecd

DMF Load DMF DMF Raw Materials

DICY Turn Steam on Preheating DICY TK

Operational ExcellenceControl Plan

The Key Inputs are evaluated for process

controlKey Inputs are explored while evaluating process for potential failure

Outputs Inputs

How Cause & Effect can Fit into Process How Cause & Effect can Fit into Process Improvement ActivitiesImprovement Activities

The Big Picture

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Example of how Cause and Effect Matrix can be used in SCAR.

Received complaint/reject

from customer, in-house or supplier.

Hold meeting with relevant

departments (if necessary)

-receive CAR reply from production- reply to customer

Follow up on CAR

Generate report for

management review

QA personnel verify the defects.

Issue CAR to production.

Purge in-house stock

Cause and Effect Matrix can be used in conjunction with fishbone diagram to identify, rank and prioritize the key causes.

Section of SCAR Procedure

Integrating Cause & Effect Matrix into SOPsIntegrating Cause & Effect Matrix into SOPs


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5.4.2.4 It is the responsibility of the EA of CMM section to set-up the trend-tests forout-of-control in the "SPC" software.

5.4.2.5 The E.A/Supervisor of the 'CMM' section shall monitor the X-R Charts on thecomputer and look-out for out-of-control situation. When out-of-control is detected, he shall analyse the subgroup data, the histogram and the prevailing Cpk value,based on these he shall decide the action to take. When the situation necessitates, a "PCAR" shall be issued to the Production E.A/Supervisor.

5.4.2.6 The Production Supervisor/E.A shall analyze the problem and take corrective actions on the process concerned, after which, new samples shall be submitted for measurement. When the problem has been rectified, Production Supervisor/EAshall write in the "PCAR" form, the corrective actions taken and return the form to the E.A or Supervisor of "CMM" section.

Example of how Cause & Effect Matrix can be used in SPC control

Section of SPC Control Procedure

Integrating Cause & Effect Matrix into SOPsIntegrating Cause & Effect Matrix into SOPs


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The effort to integrate Cause & Effect Matrix into SPC and SCAR procedures should be translated into specific tasks in the Work Breakdown Structure.S/N Tasks Task Owner Target

Completion DateSpecific Training needed for Task

Owner/ Date

Core Team Member In

Charge

Internal Verified Date

Group Phase End Date

Group 1 Tools

1 SPC

Integrate Cause and Effect Matrix in the SPC procedure/ system

Dick 10-Dec-01 Fishbone Diagram -15 Oct 2001

Cause & Effect Matrix

-15 Oct 2001


2 SCAR

Integrate Cause and Effect Matrix in the SCAR procedure/ system

Mary 10-Dec-01 Fishbone Diagram -15 Oct 2001

Cause & Effect Matrix

-15 Oct 2001


Link Tools Integration Tasks to Work Link Tools Integration Tasks to Work Breakdown StructureBreakdown Structure

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End of TopicEnd of Topic

Any question?Any question?

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Product/Manufacturing Example

NLA

Measurem ent

Method

Machine

Man

Material

S ettling o f S lu rryP artic les (C )

S lu rry F low R a te (C ) R a (C ) L ine D ens ity (C ) T ex tu re

T em pera tu re (C )

P rogram used (N ) S kew (N ) P U P ad (C ) S on ic pow er (C ) T ex tu re

T em pera tu re (C ) C a lib ra tion (N )

S lu rry S tirr ing P rocedure (C ) S oak T im e (C ) S tagg ing T im e (N ) T rans fe r T im e (C ) C om p liance to P rocedures (C )

S ettling o f P a rtic les (C ) S lu rry S tirr ing P rocedures (C ) P rogram used (N ) S peed A d jus tm en t (C ) U ltrason ic on /o ff (C ) S oak T im e (C ) S tagg ing T im e (N ) T rans fe r T im e (C ) T ex tu re T em pera tu re (C ) C oncen tra tion o f C hem ica (C ) T ape S peed (C ) S lu rry F low R a te (C ) T ex tu re P ressu re (C )

S lu rry T ype (C ) S ubs tra te (C ) T ape T ype (C ) S urfac tan t T ype (C ) P U P ad (C )

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EstimatedShip DateChanges

WCSC PRACTICES

INTRANSIT

TIMES

INVENTORYACCURACY

APPOINTMENTCUSTOMER

PLANNEDSHIP DATE

ALGORITHM

MDCCAPACITY

ESDALGORITHMANOMALIES

ORDERCANCELLATION

SCHEDULECHANGES

MDCPRACTICES

- Unrealistic Del. Req Dates - Customer Order Priority Changes

- Receiving - Picking - PC delays - Off shift support

LDSS

- Firm - Planned

- B.O.. Consol. - SC late

- Bad IT days- Table Maint.

- Availability Overrides- No Stocks

- Waiting for Delivery Appt.

- Late PT print- Late EDI data

Estimated Ship Date Change - CAUSE & EFFECT / FISHBONE

- No Delivery Constraints After initial PSD - Back Ord. Release Logic - Cust Priority vs. availability -Future orders at AP

Transactional Example

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Why Use Brainstorming?• A tool for the Team (not individual)• A method to generate a lot of ideas• Two persons’ knowledge and ideas are always more than an individual’s• Input for other C&E tools• Active participation

?

??

?

? ?A technique to A technique to

generate a large generate a large number of ideas or number of ideas or

possibilities in a possibilities in a relatively short time relatively short time

frame.frame.

Brainstorming

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How to Conduct a Brainstorming SessionHow to Conduct a Brainstorming SessionTeam Makeup Experts “Semi” experts Implementers Analysts Technical staff who will run the experiment Operators

Discussion Rules Suspend judgement Strive for quantity Generate wild ideas Build on the ideas of others

Leader’s rules for Brainstorming Be enthusiastic Capture all the ideas Make sure you have a good skills mix Push for quantity Strictly enforce the rules Keep intensity high Get participation from everybody

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How do we know when we have reached ROOT CAUSE ?

Root Cause is the lowest cause in a chain of cause and effect at which we have some capability to cause the break It’s within our capability to unilaterally control, or to influence, changes to the cause

Root CauseRoot Cause

Base castings leak at mounting screw holeSuppliers leak test may not detect porosity leak

Products are failing for contamination

Suppliers have different leak test processes

No standard process for supplier leak test

WHY?

WHY?

WHY?

WHY?Can I cause the break if I stop here?

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Span of Control / Sphere of InfluenceSpan of Control / Sphere of Influence

SPHERE OF INFLUENCE(Influence or persuasion only)

SPAN OF CONTROL(Full authority)

OUTSIDE, UNCONTROLLEDENVIRONMENT

Before we begin, we must establish the context in which the Cause-Effect will be used.

Span of Control - areas where we have a high degree of control over parts or functions, virtually complete authority to change anything

Sphere of Influence - areas where we can influence things to varying degrees but don’t have direct control.

Outside Environment - where we have neither control nor influence

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Points to Note for Fishbone DiagramPoints to Note for Fishbone Diagram

Treat the cause-and-effect diagram as a living document

As new variables are discovered, update the cause-and-effect diagram

After your experimental investigations, when you have optimized the “X” factors, and implemented control, update them to “C”.

Therefore, ideally, when the fishbone diagram has more “C”s, the better we can control the effect and improve its performance measure.

Documents

Cause and Effect Analysis: 1. Fishbone Diagram 2. Cause and Effect Matrix