Fish-bone Diagram

 The Fishbone Diagram is a tool for analyzing process dispersion. It is also referred to as the "Ishikawa diagram," because Kaoru Ishikawa developed it, and the "fishbone diagram," because the complete diagram resembles a fish skeleton. It illustrates the main causes and sub causes leading to an effect (symptom). It is a team brainstorming tool used to identify potential root causes to problems. In a typical Fishbone diagram, the effect is usually a problem needs to be resolved, and is placed at the "fish head". The causes of the effect are then laid out along the "bones", and classified into different types along the branches. Further causes can be laid out alongside further side branches. So the general structure of a fishbone diagram is presented below.

Fishbone Diagram - Structure

OBJECTIVES

The main goal of the Fishbone diagram is to illustrate in a graphical way the relationship between a given outcome and all the factors that influence this outcome. The main objectives of this tool are:

Ø  Determining the root causes of a problem.

Ø  Focusing on a specific issue without resorting to complaints and irrelevant discussion.

Ø  Identifying areas where there is a lack of data.

FIELD OF APPLICATION

The Fishbone diagram could be applied when it is wanted to:

ü  Focus attention on one specific issue or problem.

ü  Focus the team on the causes, not the symptoms.

ü  Organize and display graphically the various theories about what the root causes of a problem may be.

ü  Show the relationship of various factors influencing a problem.

ü  Reveal important relationships among various variables and possible causes.

ü  Provide additional insight into process behaviors.

PROCESS

Step 1

 We will identify and clearly define the outcome or effect to be analyzed which is health need among the Samburu community.

We shall formulate the problem (health needs) and write it in a box on the right side of the diagram. We will ensure that everyone clearly understand the nature of the health needs among the Samburu community. They will identify who is involved in health problems, and when it occurs.

Step 2

We will use a chart pack positioned so that everyone can see it, draw the spine and create the effect box.

·         Draw a horizontal arrow pointing to the right. This is the spine.

·         To the right of the arrow, write a brief description of the effect or outcome which results from the process.

·         Draw a box around the description of the health needs in Samburu

Step 3

 Identify the main causes contributing to the health needs among the samburu people. These are the labels for the major branches of our diagram and become categories under which to list the many causes related to those categories.

§  Establish the major causes, or categories, under which other possible causes will be listed. You should use category labels that make sense for the diagram you are creating.

§  Write the main categories your team has selected to the left of the effect box, some above the spine and some below it.

§  Draw a box around each category label and use a diagonal line to form a branch connecting the box to the spine.

Step 4

 For each major branch, we will let them identify other specific factors which may be the causes of the effect

They are to identify as many causes or factors as possible and attach them as sub branches of the major branches.

Fill in detail for each cause. If a minor cause applies to more than one major cause, list it under both.

Step 5

 Identify increasingly more detailed levels of causes and continue organizing them under related causes or categories. You can do this by asking a series of why questions. You may need to break your diagram into smaller diagrams if one branch has too many sub branches.

Step 6

 Analyze the diagram. Analysis helps you identify causes that warrant further investigation.

BENEFITS

Ø  Helps determine root causes

Ø  Encourages group participation

Ø  Uses an orderly, easy-to-read format to diagram cause and effect relationships

Ø  Indicates possible causes of variation

Ø  Increases knowledge of the process by helping everyone to learn more about the factors at work and how they relate

Ø   Identifies areas for collecting data

EXAMPLES – CASE STUDY

                                     

REFERENCES

1.      American Society for Quality, Fishbone diagram http://www.asq.org/learn-about-quality/cause-analysis-tools/overview/fishbone.html

2.      Balanced Scorecard Institute, Basic tools for process improvement, Module 5 – Cause and Effect diagram http://www.balancedscorecard.org/files/c-ediag.pdf

3.      Ishikawa, Kaoru (1986). Guide to Quality Control. Tokyo, Japan: Asian Productivity Organization.

4.      Walton, Mary (1992) The Deming Management Method, Mercury Business

5.      Public Health Infrastructure, Fishbone (Ishikawa) Diagram (Example) http://www.phf.org/infrastructure/PublicHealthFishbone.pdf (accessed on 25/2/2015)