The Lean Startup: How Today's Entrepreneurs Use Continuous Innovation to Create Radically Successful Businesses · chapter 3 · id the-lean-startup-c3-06-the-five-whys-technique-which-

“The Five Whys technique, which Ries recommends for root cause analysis in startups, originated at Toyota as part of the Toyota Production System.”

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Toyota Global -- Toyota Traditionssource alive

Taiichi Ohno developed the Five Whys technique as part of the Toyota Production System in the 1950s-1960s for manufacturing defect analysis.

Card (2017), Five Whys limitations, Journal of Quality TechnologyFLAGGED: DOI not in registry

Five Whys has known limitations: different analysts reach different root causes from the same starting point, it lacks systematic rigor compared to fishbone diagrams or fault tree analysis, and it is prone to confirmation bias.

American Society for Quality -- Five Whyssource alive

Five Whys is a simple but limited technique best used as a starting point, not a standalone root cause methodology.

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