NEW SEVEN MANAGEMENT TOOLS

CAUSE AND EFFECT DIAGRAMRELATIONSHIP DIAGRAM

ISHIKAWA

WHAT IS IT?

• It is a graphical tabular chart to list and analyze the potential causes of a given diagram

• Its also called as fishbone diagram because of its appearance and Ishikawa diagram after the man who developed it in 1943.

• The diagram consist of a central stem leading to effect(the problem), with multiple branches coming of the stem listing the various groups of possible causes of the problem.

When do we use it?

• The CE diagram has unlimited application in research , manufacturing, marketing, office operations, services and so forth.

• The CE diagram are used • To analyze cause and effect relationship ,• To facilitate the search for the solution of related

problem,• To standardize existing and proposed operations and• To educate and train personnel indecision making and

corrective action activities.

FORMAT OF CAUSE AND EFFECT (FISH BONE DIAGRAM)

How do we construct it?

• The CE diagram may be constructed using the following steps

1. Define the effect(the problem) clearly and concisely.2. Mark the short description of the effect in a box.

Then draw a line from this box towards left.3. List down all the possibilities minor and major causes

through a brain storming session.4. Mark the major causes on the branches and minor

causes on the sub branch of the CE diagrams.5. Look for the possible solutions for these problems.6. Introduce the changes.

CATEGORIES OF DIAGRAM The categories typically include People: Anyone involved with the process Methods: How the process is performed and the specific

requirements for doing it, such as policies, procedures, rules, regulations and laws

Machines: Any equipment, computers, tools etc. required to accomplish the job

Materials: Raw materials, parts, pens, paper, etc. used to produce the final product

Measurements: Data generated from the process that are used to evaluate its quality

Environment: The conditions, such as location, time, temperature, and culture I which the process operate.

TYPES OF TOOLS IN INDUSTRIES

EXAMPLE OF CAUSE AND EFFECT

• Once all the ideas have been added to the fishbone diagram, the next step is to discuss the ideas and clarify any ideas that are not clearly understood. For example, suppose your team has brainstormed possible causes of why the car will not start. A possible fishbone diagram is shown here

EXAMPLE OF CAUSE AND EFFECT DIAGRAM

CAUSE AND EFFECT DIAGRAM EXAMPLE

ELIMINATE NON-CAUSES• The next step is to eliminate the ideas that everyone agrees

would really not cause the problem. Everyone must agree. If one person does not agree, it must stay on the diagram as a possible cause. For example, suppose we know we have the key to the car. We could simply strike through that cause as shown in the fishbone. We have decided a couple of other "potential" causes of the car are not really causes. A line is drawn through those causes as well.

• A word of caution: even though an idea is eliminated as a possible cause, it is best to leave it on the fishbone diagram. You may circle it or strike through it. However, always keep the fishbone diagram with all the ideas on it. This will allow you to return at a later date to determine if you have eliminated true causes of the problem.

ELIMINATE NON CAUSES

HOW LIKELY IT WORKS,?• The next step is to examine each idea and determine the degree to which

the idea is an actual cause of the problem. There are numerous ways this can be accomplished. If there are not many ideas, consensus could be reached by discussing each idea individually. However, if there are many ideas on the fishbone, a "straw" vote can be used to determine the degree to which that idea is an actual cause of the problem.

• In a straw vote, each team member may vote as many times as he or she wishes. Even though this sounds as if deadlock will happen, it seldom does. Instead, each team member begins to understand where others see root causes to be. For each idea on the fishbone, each team member "votes" one of the following for how likely the listed idea is to be a cause of the problem:

• Very likely (V)

• Somewhat likely (S)

• Not likely (N)

RANKING FOR THE CAUSES

• Whichever answer receives the most votes, the corresponding letter (V, S or N) is noted beside that cause on the fishbone diagram.

• For example, the team decided that "No gas" was not a likely cause because they knew gas was in the car. So, "No gas" gets a "N" for not likely. This process is repeated for each item on the fishbone

HOW LIKELY IT WORKS