5 Whys: what it is and what it means

The 5 whys are a root cause analysis technique originally attributed to Sakichi Toyoda and systematized by Taiichi Ohno at Toyota: you repeatedly ask "why?" of every answer you get, until you reach a structural cause that leads to an action different from the initial one. The technique is an analysis tool within the PDCA or A3 phases, not an alternative to the process.

Distinctive: you repeatedly ask "why?" of every answer
Distinctive: leads to an action different from the initial one
Essential: structural cause
Essential: root cause analysis
Constant: analysis tool within the PDCA or A3 phases

Glossary

5 Whys

A root cause analysis technique that repeatedly asks "why?" until it reaches a structural cause that leads to an action different from the initial one.