A Comprehensive Guide to 5 Why Analysis

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1 5 Whys Example — The Vehicle will not Start

3 Creating 5 Whys Analysis Using Online Spreadsheet

For every effect there is a cause. The “5 Whys” is a technique originally used by the Toyota Motor Corporation to explore cause-and-effect relationships. It is an iterative interrogative technique used to explore the cause-and-effect relationships underlying a particular problem.

The primary goal of the technique is to determine the root cause of a 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.

“The basis of Toyota’s scientific approach is to ask why five times whenever we find a problem“
” By repeating why five times, the nature of the problem as well as its solution becomes clear.“ by Taiichi Ohno

5 Whys Example — The Vehicle will not Start

Why? — The battery is dead
Why? — The alternator is not functioning
Why? — The alternator Belt has broken
Why? — The alternator belt was well beyond its useful service life and not replaced
Why? — The vehicle was not maintained according to the recommented service schedule

Present 5 Whys using Infographic Template