5 x WHY (Form) attached

[Jim Wynne]

In Reply to Parent Post by Big Jim

Don't get carried away with the number "5" in five why.

Although you can usually get to the true root cause by going through the exercise of asking why and determining if it is the final why in five iterations, it may actually take more or less than five.

Don't get tunnel thought on the number five. It takes as many as it takes, whether it take two or eight, the concept of five why still can be applied.

I always wondered about the 5-why thing. If a person isn't smart enough to know when he's found the answer (and must be prompted to keep asking "why?"), how can he be smart enough to know when to stop at all? It doesn't make sense on any level.

[Umang Vidyarthi]

In Reply to Parent Post by Jim Wynne

I always wondered about the 5-why thing. If a person isn't smart enough to know when he's found the answer (and must be prompted to keep asking "why?"), how can he be smart enough to know when to stop at all? It doesn't make sense on any level.

I agree with you Jim.

Taiichi Ohno (architect of TPS), 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." This method of root-cause-analysis went beyond Toyota and spread over the world. Taichi Ohno felt that five iterations of 'why' would suffice to surface any problem, and it became a rule of thumb. But in TPS (Toyota Production System) too, asking 'whys' was not restricted to five times. Despite going beyond 'five times' at times, this method continued to carry the original title '5-why'.

Later, someone (perhaps Peter Scholtes) started using the '5-why' analysis under the name of 'why-why' analysis, and today both the nomenclatures are concurrently in use.

Umang

[dyonisius]

Really good info here folks, thank you very much.