5 Whys

One downside of the Five Whys exercise is that brainstormers tend to mistake symptoms of the root cause for the actual root cause. When this happens, participants tend to stop investigating, thinking they found the problem – when they should be tracing the symptoms back to lower-level root causes.

Assess the process, rather than the people; human error should not be labeled the problem.

Five Whys is used in the "analyze" phase of the Six Sigma DMAIC (define, measure, analyze, improve, control) methodology.