1. Fishbone Diagram/ Cause & Effect Diagram

2. WHERE DOES THE NAME COME FROM?
The Fishbone Diagram also referred to as the Ishikawa diagram, because Kaoru Ishikawa developed it, and the fishbone diagram, because the complete diagram resembles a fish skeleton.

3. Where to start a cause and effect analysis?
Brainstorm
Conduct a Brainstorm of all the possible causes of the effect, i.e., problem.
Have a mixed team from different parts of the process (e.g., assemblers and testers).
Get a “fresh pair of eyes” - from someone who is not too close to the process.
Have a facilitator - an impartial referee.
Everyone is an equal contributor (“leave stripes at the door”).
Fast and furious - go for quantity rather than quality (of ideas) at first.
Involve everyone, or question why he/she is here.
Timing - set an upper limit and best time/day of the week.
Offer an incentive (free lunch?).
Know when to stop.
Recognize that this is a snapshot of how the group thinks today.
Re-visit the problem again.
Refer also to the Process Mapping tool.
Consider (how) should you involve your customer?

4. WHAT DOES IT DO?
It illustrates the main causes and sub causes leading to an effect (symptom).
It is a brainstorming tool used to identify potential root causes to problems

5. HOW IS IT DONE?
The symptom or result or effect for which one wants to find causes is put in the box on the right.
Unable to complete project on time

6. HOW IS IT DONE?
The causes and its factors are identified and entered as branches to these main groups.
External
Materials
Man
Unable to complete project on time
Funds
Methods
Machines

7. Analyse for Root Causes
Consider which are the most likely root causes of the effect. This can be done in several ways:
Through open discussion among participants, sharing views and experiences. This can be speeded up by using Consensus Decision Making.
By looking for repeated causes or number of causes related to a particular category.
By data gathering using Check Sheets, Process Maps, or customer surveys to test relative strengths through Pareto Analysis.
Once a relatively small number of main causes have been agreed upon, Paired Comparisons, can be used to narrow down further.
Some groups find it helpful to consider only those causes they can influence.

8. HOW IS IT DONE? Materials Man External Funds Methods Machines
Availability
Expertise
Quality
Delivery
Purchase
Unable to complete project on time
Maintenance
Utilisation
Availability
Performance
Availability
Funds
Methods
Machines
The sub reasons or sub factors are linked to the factors.

9. Sources of Variation - People
The activities of the workers.
Variations caused by skill, knowledge, competency and attitude
Types of Questions that may be Asked Note, this is not a definitive list of questions that may be asked to identify potential source of variation
Does the person have adequate supervision and support?
Does the person know what he is expected to do in his job?
How much experience does the person have?
Does the person have the proper motivation to do his best work?
Is the person satisfied or dissatisfied with his job?
Is the person more- or less-productive at certain times of the day?
Do physical conditions such as light or temperature affect their work?
Does the person have the tools/equipment needed to do the job?
Who does the person contact when problems arise?
Is the work load reasonable?

10. Sources of Variation - Method
The methods used to produce the products.
Variations caused by inappropriate methods or processes.
Types of Questions that may be Asked
How is the method used defined?
Is the method regularly reviewed for adequacy?
Is the method used affected by external factors?
Have other methods been considered?
How does the operator know if the method is operating effectively?
Is statistical analysis used to verify the effectiveness of the method?
What adjustments must the operator make during the process?
Have any changes been made recently in the process?

11. Sources of Variation - Machine
The equipment used to produce the products.
Variations caused by temperature, tool wear and vibration.
Types of Questions that may be Asked
How old is the equipment or machinery?
Is it maintained regularly?
Is the machine affected by heat or vibration or other physical factors?
How does the operator know if the machine is operating correctly?
Is statistical analysis used to verify the capability of the machine?
What adjustments must the operator make during the process?
Have any changes been made recently in the process?

12. Sources of Variation - Material
The "ingredients" of a process.
Variations caused by materials that differ by industry, product and stage of production.
Types of Questions that may be Asked
How is the material produced?
How is the material verified?
How old is the material?
How is quality judged prior to your operation?
What is the level of quality?
How is the material packaged?
Can temperature, light or humidity affect the material quality?
Who is the material supplier?
Has there been a change in suppliers?

13. Sources of Variation - Environment
The methods used to control the environment.
Variations caused by temperature changes, humidity.
Types of Questions that may be Asked
How are environmental conditions monitored?
How are environmental conditions controlled?
How is the environment control measuring equipment calibrated?
Are there changes in conditions at different times of the day?
How does environmental change impact the processes being used?
How does environmental change impact the materials being used?

14. Sources of Variation – Measurement System
The methods and instruments used to evaluate products.
Variations caused by measuring techniques, or calibration and maintenance of the instruments.
Types of Questions that may be Asked
How frequently are products inspected?
How is the measuring equipment calibrated?
Are all products measured using the same tools or equipment?
How are inspection results recorded?
Do inspectors follow the same procedures? (Is there a set of standards?)
Do inspectors know how to use the test equipment?

15. Cause and effect diagram
External
Materials
Man
Training
Availability
Expertise
Quality
Delivery
Purchase
Unable to complete project on time
Multi use
Approval
Maintenance
Utilisation
Availability
Performance
Availability
Funds
Methods
Machines

16. SAMPLE2 PART DIMENSIONAL QUALITY MACHINE METHOD MANPOWER MATERIAL
PROCESS KNOWLEDGE
TRAINING
SHIFT
OVERTIME
INSPECTION AVAILABILITY
THERMAL EXPANSION
PART DEFORMATION
MACHINABILITY
STRENGTH
REPEATABILITY
POSITIONING ACCURACY
BACKLASH
RIGIDITY
NC PROGRAM
FEED
FORCE
SPEED
TEMP
CUT DEPTH
TOOL PATH
INSERT
TYPE
GRADE
HOLDING FIXTURE
GAUGE
REPRODUCABILITY
COOLANT