5 Why

5 why is an iterative interrogative technique to search the Cause and Effect relationships fundamental a particular problem. The primary goal of the technique is to find ascertain the Root Cause of a defect or problem by repeating the question “Why?”.

History

The “5 Whys” technique was developed by Sakichi Toyoda in the 1930s. He was an industrialist, inventor, and founder of Toyota industries. His method became popular in the 1930s, and Toyota still uses it to problems solving.

How to use 5 Why

We can use 5 why for troubleshooting and problem solving, but it can most in effect when used to resolve simple and passably difficult problems.

Gather the people who are associated with the detail of the problem and with the process that you’re trying to resolve.

Observe the problem within the action. Discuss with your team and write the brief of the problem, clear problem statement that you all agree on.

Then write your statement on the whiteboard and leave enough space around it to write the answer.

Ask your team why the problem is occurring?

When you get the answer ask further why’s.

You’ll have revealed the nature of the root cause when asking why produces no more useful responses and you can go no further.

Now you’ve identified at least one true root cause, you need to discuss and agree what countermeasure will prevent the problem from recurring.

Keep a close view on how effectively your counter-measure eliminate or reduce the problem.

Example

The battery will not start. (problem)

Why? – The battery is dead.

Why? – The alternator is not functioning.

Why? – The alternator belt has broken.

Why? - The alternator belt was well beyond its useful service life and not replaced.

Why? - The vehicle was not maintained according to the recommended service schedule.

Rules of performing 5Why

Use paper or whiteboard instead of a computer.

Write down the problem and make sure that all people understand it.

Pay attention to the logic of cause-and-effect relationship.

Try to make your answer more exact.

Built an atmosphere of trust and sincerity.