QUALITY TOOLS : CAUSE AND EFFECT DIAGRAMS

HISTORY

• Known as Ishikawa Diagrams or Fishbone Diagrams.
• Created by Kaoru Ishikawa in 1968.
• Common uses of the Ishikawa diagram are product design and quality defect prevention to identify potential factors causing an overall effect.
• The CE Diagram is basically used to investigate a problem, exploring, identifying, and displaying the possible causes.
• To identify the relationship between the  effects in a given situation and all of the possible causes.
• To find problem sources and solutions.
• It helps determine the root causes of a problem using a structured approach.

TYPES

•        Manufacturing Industry 6 M’s    Service Industry 5 S’s                             

1. Measurement                            1. Surroundings
2. Material                                     2. Suppliers
3. Machine                                    3. Systems
4. Man Power                               4. Standard Documentation Skills
5. Method                                     5. Scope of Work
6. Mother Nature

•         Marketing Industry 8 P’s       Sales Industry 5S’s

1. Product                                      1. Samples
2. Place                                          2. Schemes
3. Price                                           3. Synchronous
4. People                                        4. Skin
5. Promotion                                   5. Search
6. Process
7. Physical Evidence
8. Packaging

PROCESS

1. Identify the problems to be corrected.
2. Identify any possible causes of the  problem.
3. Question the cause of problems in each area, seeking changes that are
    deviations from the norm.
4. Repeat for each sub-area.

 ADVANTAGES

1. Display relationships clearly and logically.
2. Show all causes simultaneously.
3. Facilitate brainstorming.
4. Stimulate problem solving.
5. Help maintain team focus.

DISADVANTAGES

1. It doesn’t solve any problems.
2. Makes all possible causes look equally plausible and equally important.
3. Does not offer any possible solutions or analysis.

FISHBONE DIAGRAMS