Five Whys

A technique used to probe the root causes of a problem. Popularized by Toyota in the 1970s, this strategy involves looking at any problem and asking: “Why?” and “What caused this problem?” The answer to the first “why” prompts another “why” and then another, and so on.

Why (why) (why) (why) (why):
It’s not uncommon for a project to focus on the symptoms of a problem, rather than exposing the underlying causes. By asking why, and why, and why again, we gain insight that allows us to address real problems in a way that will make a real difference.

Formalized by Toyota in the 1970s, Five Whys was popularized by Six Sigma.