Bugün öğrendim ki: Sakichi Toyoda (d. 1867, d. 1930, Toyota endüstrilerinin kurucusu) tarafından, "Neden?" sorarak bir kök neden bulunana kadar semptomlar üzerinde çalışmanın bir yöntemi olarak icat edilen Beş Neden yönteminin bir örneği. Beş kere.

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Iterative interrogative technique **Five whys** (or **5 whys** ) is an [iterative](/wiki/Iteration "Iteration") interrogative [technique](/wiki/Skill "Skill") used to explore the [ cause-and- effect](/wiki/Causality "Causality") relationships underlying a particular problem.[1] The primary goal of the technique is to determine the [root cause](/wiki/Root_cause "Root cause") of a [defect](https://en.wiktionary.org/wiki/defect "wikt:defect") or problem by repeating the question "Why?". Each answer forms the basis of the next question. The "five" in the name derives from an anecdotal observation on the number of iterations needed to resolve the problem. Not all problems have a single root cause. If one wishes to uncover multiple root causes, the method must be repeated asking a different sequence of questions each time. The method provides no hard and fast rules about what lines of questions to explore, or how long to continue the search for additional root causes. Thus, even when the method is closely followed, the outcome still depends upon the knowledge and persistence of the people involved.