![]() ![]() It is a critical component of problem-solving training, delivered as part of the induction into the Toyota Production System. The technique was originally developed by Sakichi Toyoda and was used within the Toyota Motor Corporation during the evolution of its manufacturing methodologies. Therefore, instead of asking why?, ask why did the process fail? History These answers may be true, but they are out of our control. Untrained facilitators will often observe that answers seem to point towards classical answers such as not enough time, not enough investments, or not enough resources. This is one of the most important aspects in the five why approach – the real root cause should point toward a process that is not working well or does not exist. In this example, the fifth "why" suggests a broken process or an alterable behavior, which is indicative of reaching the root-cause level. The key is to encourage the troubleshooter to avoid assumptions and logic traps and instead trace the chain of causality in direct increments from the effect through any layers of abstraction to a root cause that still has some connection to the original problem. The questioning for this example could be taken further to a sixth, seventh, or higher level, but five iterations of asking why is generally sufficient to get to a root cause. Why? – The vehicle was not maintained according to the recommended service schedule.Why? – The alternator belt was well beyond its useful service life and not replaced.Why? – The alternator is not functioning.Others at Toyota and elsewhere have criticized the five whys technique for various reasons (see § Criticism).Īn example of a problem is: the vehicle will not start. The technique was described by Taiichi Ohno at Toyota Motor Corporation. The answer to the fifth why should reveal the root cause of the problem. The primary goal of the technique is to determine the root cause of a defect or problem by repeating the question "Why?" five times. Five whys (or 5 whys) is an iterative interrogative technique used to explore the cause-and-effect relationships underlying a particular problem. ![]()
0 Comments
Leave a Reply. |