5 x Why

Description

The '5 x why' method is a simple but highly effective tool for identifying the root cause of a problem. The '5 x why' method was developed by Toyota to perform root-cause analysis for production-related problems. Due to its simple design and effective output, the '5 x why' method has also become a part of Kaizen and Lean Six Sigma processes.

When

In the Analyse Causes phase.

Goals

When a problem is identified, it is usually at the surface. That is, the visible problem is actually a symptom of one or more problems that lie underneath. And those underlying problems are called root causes. To know where the real problem is coming from and how to solve it permanently, you have to look for these root causes.

Using the '5x why' method, we try to uncover root causes.

Steps

Identify the problem for which the root-cause needs to be identified Ask the question "Why did this problem arise? The result is an answer with yet another new or different problem.
Take the first answer (or problem) and ask the question again: why did this problem arise?
Repeat these steps until you get to the core (root-cause) of the problem

Figure: 5 x why method

Examples

Example 5 x why method

Tips:

To avoid employees feeling held accountable or feeling judged for their work, the why question can be replaced by: how do you think it is because...? Or: what makes...?
Make sure the answers are based on facts that can actually be ascertained.
The '5 x why' method is good to use when using a fishbone diagram to clarify root causes. Ask 5 times when a participant names a cause.