Getting to the Bottom of the Matter

The 5 ‘Whys’

“If you don’t ask the right questions, you don’t get the right answers. A question asked in the right way often points to its own answer. Asking questions is the ABC of diagnosis. Only the inquiring mind solves problems.” – Edward Hodnett

Definitions for this article:

Root Cause – A root cause is an initiating cause of either a condition or a causal chain that leads to an outcome or effect of interest. Basically, the true reason why something happened.

Six Sigma - Six Sigma at many organizations simply means a measure of quality that strives for near perfection. Six Sigma is a disciplined, data-driven approach and methodology for eliminating defects (driving toward six standard deviations between the mean and the nearest specification limit) in any process – from manufacturing to transactional and from product to service. – Source: iSixSigma.com

Getting to the bottom of the matter, the root cause, can take some skill; however, it is one of the most useful skills one can have. In order to do so, it is imperative that the analyst or investigator use a standard process. An effective way to find a root cause is using a Six Sigma tool known as 'The 5 Whys”.

If you keep asking ‘why’, you will eventually find the answer(s) you are looking for. This method is useful when dealing with human factors, interactions, and daily business operations. Although the tool is known as ‘the 5 Whys’, it may take less or more than 5 times in order to identify a true root cause.

Here is an example of a root cause analysis (RCA) using ‘the 5 Whys’ from Toyota:

Problem: The robot stopped working.

1. "Why did the robot stop?" The circuit has overloaded, causing a fuse to blow.
2. "Why is the circuit overloaded?" There was insufficient lubrication on the bearings, so they locked up.
3. "Why was there insufficient lubrication on the bearings?" The oil pump on the robot is not circulating sufficient oil.
4. "Why is the pump not circulating sufficient oil?" The pump intake is clogged with metal shavings.
5. "Why is the intake clogged with metal shavings?" Because there is no filter on the pump.

Root cause: Due to there being no filter in the oil pump, the intake became clogged, causing the poor circulation of oil in the robot. In turn, there was insufficient lubrication on the bearings, causing the robot to stop working.

Asking ‘the 5 whys’ will identify the true root cause of a problem. After finding a root cause, it is up to you and your team to make actionable items to address the root cause.

Steps to Problem Solving

1. Identify the problem
2. Ask the right questions
3. Identify the root cause(s)
4. Identify actionable items
5. Take action