Comment by Mikerad1979

This technique is called a 5-Why in lean manufacturing. Useful tool in digging into a root cause, and helps people think deeply about the causes of issues that are not inherently obvious.

Also, 5 is just the "suggested" number. More or less may be needed. If you reach 'Because I don't want to die alone' in 3 whys, probably no need to try for 5...