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professionals. Every effort has been made to ensure the accuracy of any calculations, however no guarantee is expressed or implied as to its accuracy. If you have suggestions for improvement please

feel free to contact 6ixSigma.org

This product is copyrighted and protected by federal law. However, feel free to distribute or share with other Six Sigma

professionals. Every effort has been made to ensure the accuracy of any calculations, however no guarantee is expressed or implied as to its accuracy. If you have suggestions for improvement please

feel free to contact 6ixSigma.org

5 Why'sBy asking successive 'Why's' the team may be able to identify Root Cause

Therefore

Is Confirmation Necessary?Therefore Yes

No

Therefore Yes

No

Therefore Yes

No

Therefore Yes

NoHow is this confirmed?

Yes

Root Cause

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What is the failure?The car won't start

Why did this occur?It ran out of gasoline

How is this confirmed?Manual Fuel level check

Why did this occur?I forgot to fill it up

How is this confirmed?Last receipt available

Why did this occur?The fuel gage is not working

How is this confirmed?Fuel gage testing

Why did this occur?I forgot to have it repaired

How is this confirmed?Maintenance records

Why did this occur?I didn't put it on the repair list when it broke

Be sure the 5 Why's is grounded in observation not deduction

5 Why'sBy asking successive 'Why's' the team may be able to identify Root Cause

Instructions:

STEP 1 : Define the problem. What is the product, process or service that has failed.

STEP 2 : Ask: Why did this occur?

STEP 3 : Answer: Does this reason need to ne confirmed? If No proceed to next 'Why?' If Yes, then record how confirmation was made.

STEP 4 : Repeat Step 2 & 3 until Root Cause is identified.

STEP 5 : Verify Root Cause by starting at the probable Root Cause and connecting it to the previous cause using 'Therefore'

STEP 6 : Repeat Step 5 until you reach the problem

STEP 7 : If there is a logical connection between each pair of statements back to the problem then you have likely found the Root Cause

How is this confirmed?

How is this confirmed?Manual Fuel level check

How is this confirmed?Last receipt available

How is this confirmed?

How is this confirmed?Maintenance records

STEP 1 : Define the problem. What is the product, process or service that has failed.

STEP 3 : Answer: Does this reason need to ne confirmed? If No proceed to next 'Why?'

STEP 5 : Verify Root Cause by starting at the probable Root Cause and connecting