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

2. Learning 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

3. What do you mean by “ Cause & Effect”?
A PROBLEM WHICH
HAS OCCURED
A POTENTIAL
FUTURE PROBLEM
(FMEA)
EFFECT
Symptoms that
provide evidence
of the problem
EFFECT
Symptoms that
would result
from the problem
CAUSE
Events/conditions
that led to
the problem
CAUSE
Events/conditions
that would lead to
the problem .
Dave Wessel, “An Ounce of Prevention”, Quality Progress, Dec, 1998

4. Cause - Effect Relationship
A PROBLEM WHICH
HAS OCCURED
EFFECT
Symptoms that
provide evidence
of the problem
ACTION
CORRECTIVE
Eliminates the
of a problem
CAUSE
problem or deviation
ADAPTIVE
Limits the
EFFECT of a
CAUSE
Events/conditions
that led to
the problem
Dave Wessel, “An Ounce of Prevention”, Quality Progress, Dec, 1998

5. Fishbone Diagram

6. 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.
Methods
Materials
Machinery
Manpower
Problem/
Desired
Improvement
C/N/X C N

7. Dr 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

8. 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

9. Constructing a Fishbone Diagram
Establish what the problem (effect) is
It must be stated in clear and concise terms, agreed by everyone.
Write the effect on the head of the fish
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 Minitab

10. Constructing a Fishbone Diagram
Stat ðQuality Tools ðCause-and-Effect

11. Constructing a Fishbone Diagram
Fishbone Diagram for Surface Flaws
Measurements
Materials
Man
List specific causes in each category
Surface Flaws
Problem (effect)
at the “head of
the fish”
Environment
Methods
Machines
Major categories of causes
(or sometimes call major bones)
Why do we need to group the causes?

12. Constructing a Fishbone Diagram
4. Identify possible causes through Brainstorming
Identify specific causes within each major category that may be affecting the problem.
Fishbone Diagram for Surface Flaws
3. Continue asking: ‘Why is this happening?’ until you no longer get useful information.
Measurements
Materials
Personnel
2. Repeat this procedure with each specific cause to produce sub-causes.
Micrometers
Calibration Method
Alloys
Shifts
Calibration Interval
Precision
Accuracy
Lubricants
Supervisors
Microscopes
Suppliers
Training
Inspectors
Operators
Surface Flaws
Machine feedrate
Speed
Machine rpm
Brake
Lathes
Brand of bit
Condensation
Engager
Bits
Size of bit
1. The team should ask : ‘What are the machine issues affecting/causing the problem?’
Moisture%
Angle
Sockets
Environment
Methods
Machines
When do we know we have reached the root cause ?

13. Analyzing 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

14. Analyzing a Fishbone Diagram
6. The team should analyze and zoom in those “most likely causes”.
Helpful Hint
Look 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.

15. Integrating Fishbone Diagram into SOPs
Example of how fishbone diagram can be used in SCAR.
Section of SCAR Procedure
Received complaint/reject from customer, in-house or supplier.
Generate report for management review
Fishbone diagram can be used here to brainstorm/ identify root causes
QA personnel verify the defects.
Follow up on CAR
Issue CAR to production.
-receive CAR reply from production
- reply to customer
Purge in-house stock
Hold meeting with relevant departments (if necessary)
Fishbone diagram can be used here to brainstorm/ identify root causes.
To prioritize and work on most likely causes.
Should also update Fishbone diagram

16. Integrating Fishbone Diagram into SOPs
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

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

18. Cause & Effect Matrix

19. Cause and Effect Matrix

20. Description: 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)
Results
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

21. Constructing a Cause & Effect Matrix
1. List key outputs (Y’s)

22. Constructing a Cause & Effect Matrix
2. Rank Y’s with respect to customer importance

23. Constructing a Cause & Effect Matrix
3. List key inputs (X’s)
Input Variables

24. Constructing a Cause & Effect Matrix
You are ready to correlate customer requirements to the process input variables
Avoid confusion and inconsistency by establishing scoring criteria:
0 = no correlation
1 = the process effect only remotely affects the customer requirement
4 = The input variable has a moderate effect on the customer requirement
9 = The input variable has a direct and strong effect on the customer requirements
Note: Not recommended to use more than 5 different criteria.

25. Constructing a Cause & Effect Matrix
4. Relate X’s to Y’s
X’s
Y’s

26. Constructing a Cause & Effect Matrix
5. Cross-multiply and add
Key inputs are now ranked in importance with respect to the key outputs
So??

27. How Cause & Effect can Fit into Process Improvement Activities
C&E Matrix
The Big Picture
Outputs
Inputs
Capability Summary
Control Plan Summary
FMEA
The Key Outputs are evaluated ability to meet customer spec.
The Key Inputs are evaluated for process control
Key Inputs are explored while evaluating process for potential failure

28. Integrating Cause & Effect Matrix into SOPs
Example of how Cause and Effect Matrix can be used in SCAR.
Section of SCAR Procedure
Received complaint/reject from customer, in-house or supplier.
Generate report for management review
Cause and Effect Matrix can be used in conjunction with fishbone diagram to identify, rank and prioritize the key causes.
QA personnel verify the defects.
Follow up on CAR
Issue CAR to production.
-receive CAR reply from production
- reply to customer
Purge in-house stock
Hold meeting with relevant departments (if necessary)
Cause and Effect Matrix can be used in conjunction with fishbone diagram to identify, rank and prioritize the key causes.

29. Integrating Cause & Effect Matrix into SOPs
Example of how Cause & Effect Matrix can be used in SPC control
Section of SPC Control Procedure
Cause and Effect Matrix can be used in conjunction with fishbone diagram to identify, rank and prioritize the key causes.

30. Link Tools Integration Tasks to Work Breakdown Structure
The effort to integrate Cause & Effect Matrix into SPC and SCAR procedures should be translated into specific tasks in the Work Breakdown Structure.

31. End of Topic Any question?

32. Product/Manufacturing Example

33. Transactional Example
Estimated Ship Date Change - CAUSE & EFFECT / FISHBONE
MDC
PRACTICES
MDC
CAPACITY
WCSC
PRACTICES
SCHEDULE
CHANGES
- Unrealistic
Del. Req
Dates
- Customer Order
Priority Changes
- B.O.. Consol.
- SC late
ORDER
CANCELLATION
- Firm
- Planned
- Receiving
- Picking
- PC delays
- Off shift support
Estimated
Ship Date
Changes
- Bad IT days
- Table Maint.
- Waiting for
Delivery Appt.
PLANNED
SHIP DATE
ALGORITHM
- No Delivery Constraints
After initial PSD
- Back Ord. Release Logic
- Cust Priority vs. availability
-Future orders at AP
- Availability
Overrides
- No Stocks IN
TRANSIT
TIMES
- Late PT print
- Late EDI data
INVENTORY
ACCURACY
APPOINTMENT
CUSTOMER
ESD
ALGORITHM
ANOMALIES
LDSS

34. Brainstorming ? ? ?
A technique to generate a large number of ideas or possibilities in a relatively short time frame. ? ? ?
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

35. How to Conduct a Brainstorming Session
Team 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

36. How do we know when we have reached
Root Cause
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
Base castings leak at mounting screw hole
Suppliers 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?
Can I cause the break if I stop here?

37. Span of Control / Sphere of Influence
Before we begin, we must establish the context in which the Cause-Effect will be used.
SPHERE OF INFLUENCE
(Influence or persuasion only)
SPAN OF CONTROL
(Full authority)
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
OUTSIDE, UNCONTROLLED
ENVIRONMENT

38. Points 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.