What is 5 Whys?

The 5 Whys is an iterative interrogative technique used to explore the cause-and-effect relationships underlying a particular problem. The primary goal is to determine the root cause of a defect or problem by repeatedly asking the question "Why?". Each answer forms the basis of the next question. The "5" in the name is anecdotal, suggesting that five iterations are often sufficient to resolve the problem. This technique is often used in lean manufacturing and problem-solving methodologies.