Vadim Kotelnikov    

5-Why Process

Discovering the Root Causes of a Problem


Business e-Coach     


"He who asks a question may be a fool for five minutes,
but he who never asks a question remains a fool forever."
~ Tom Connelly


Problem Solving The Five-Why Method Toyota Production System (TPS) 5 Why Method, The Five-Why Process for Problem Solving in Kaizen and Lean Manufacturing (Toyota)


Taiichi Ohno, former Toyota vice president, once gave the following example of finding the real cause of a machine stoppage.1

Q1: Why did the machine stop?

A1: Because the fuse blew due to an overload.

Q2: Why there was an overload?

A2: Because the bearing lubrication was inadequate.

Q3: Why was the lubrication inadequate?

A3: Because the lubrication pump was not functioning right.

Q4: Why wasn't the lubrication pump working right?

A4: Because the pump axle was worn out.

Q5: Why was it worn out?

A5: Because sludge got in.

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1. "Kaizen: The Key To Japan's Competitive Success," Masaaki Imai


The Five-Why Process

Are you solving problems  or juggling symptoms?

The Five Whys is a simple but great technique to use to solve problems. It is a question-asking method used to explore the cause/effect relationships underlying a particular problem. Ultimately, the goal of applying the 5 Whys method is to determine a root cause of a defect or problem.

4 WHYs of True Success

In most situations, real problems and root causes are obscured by apparent problems. The intent of the "Five-Why" procedure is to assure that the route causes and not merely superficial symptoms are corrected. The "Five-Why Process" was introduced at Toyota to find solution to manufacturing problems, but this approach can be applied to any other area as well. Ask "Why this problem happened?" to discover its underlying problem; then ask "Why?" again to go deeper by another level until you reach the root cause.

Asking "why" repeatedly, possibly more than five times, directs the focus toward real causes so problems can be solved permanently.

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The Origin of the Five-Why Technique

The technique was originally developed by Sakichi Toyoda and was later used within Toyota Motor Corporation during the evolution of their manufacturing methodologies. It is a critical component of problem solving training delivered as part of the induction into the Toyota Production System. The architect of the Toyota Production System, Taiichi Ohno, described the 5 whys method as "the basis of Toyota's scientific approach . . . by repeating why five times, the nature of the problem as well as its solution becomes clear." The tool has seen widespread use beyond Toyota, and is now used within Kaizen, lean manufacturing, and Six Sigma. The 5 Whys really gets people involved using their brains and challenging the ‘status quo.’...  >>> More

Kaikaku and the Five-Why Technique

Radical Improvement (Kaikaku): Kore 10 Tips

"Ask "Why" five times," advises Hiroyuki Hirano in his "10 Kaikaku Commandments“ that provide a roadmap for radical improvements Download PowerPoint presentation, pdf e-book.

Norman Bodek, a Lean Manufacturing guru, writes in his comments to the 10 commandments, "In the mid-nineteen eighties I took Dr. Shingo to Granville-Phillips a manufacturer of vacuum testing equipment in Boulder, Colorado. Granville-Phillips had brilliant engineers, but they took four months to bring a new product to market (and then the result was 97% defects in final inspection). Dr. Bills, the CEO of Granville-Phillips, asked Dr. Shingo to please look at their manufacturing process to see if he could help them become more efficient. Shingo at first went to where the process originated. We went to watch the design engineers and then we followed a logical progression through the entire manufacturing process. At each stage engineers and managers would present problems to Dr. Shingo and he would carefully think and look and then instead of just giving the answer, he would ask the engineers some very basic questions. He loved to use the Five Whys, asking why five times.”



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The ‘no blame’ concept is fundamental to successful implementation of Continuous Improvement  Download PowerPoint presentation, pdf e-book, just-in-time (JIT) and problem solving  Download PowerPoint presentation, pdf e-book strategies and programs... More