5 Why Analysis is a simple approach for exploring root causes and instilling a “Fix the root cause, not the symptom,” culture at all levels of a company. The 5 Why Analysis was originally developed by Toyota founder Sakichi Toyoda and was later used within Toyota Motor Corp. during the development of the Toyota Product System (TPS). At Toyota, 5 Whys is still a critical component of problem-solving training, and the method is still widely applied within the company when problems occur.
“Toyota Business Practices dictates using the ‘Five Whys’ to get to the root cause of a problem, not the ‘Five Whos’ to find a fire the guilty party.” – Jeff Liker, The Toyota Way
It can be used whenever the real cause of a problem or situation is not clear. Using the 5 Whys is a simple way to try solving a stated problem without a large detailed investigation requiring many resources. When problems involve human factors this method is the least stressful on participants. It is one of the simplest investigation tools easily completed without statistical analysis. Also known as a Why Tree, it is supposedly a simple form of root cause analysis. Application of the procedure involves taking any problem and asking “Why – what caused this problem?” Then, when the cause is identified, asking “Why?” again (i.e. “what caused the cause?”) The strategy, as commonly understood, is to ask “Why” five times or more uncovering links in a causal chain going back in time. By repeatedly asking the question, ‘Why?’ you peel away layers of issues and symptoms that can lead to the root cause.… Read the rest