Lean Manufacturing in Simple Terms: 5 Why's

More Lean Manufacturing Methods Expressed in Everyday Language

There are several established failure analysis methods that have been proven to be effective in the manufacturing world. "Fish bone" analyses and cause-and-effect diagrams are examples of two widely used tools for discovering what is wrong in a particular situation, such that a corrective action can be taken. In many cases, however, these take time and energy to put together. Perhaps a simpler approach, such as the 5 Why's method, would help to find the source of a problem a little quicker, possibly avoiding the need for other research-intensive efforts. The 5 Why's method, a recognized lean manufacturing technique, challenges those working an issue to peel back the layers of a problematic situation one at a time, hopefully exposing a root cause that can be corrected.

5 Why's - What is it? If you are a parent, you will recognize the fact that most children use this method on a frequent basis, partially out of natural curiosity, and partially to drive a parent nuts.

"Dad, why can't I have my dessert?"

"Because you didn't eat your vegetables."

"Why do I have to eat my vegetables?"

"So you'll have a strong body and not get sick."

"Why do vegetables help me stay strong?"

Usually, at this point, when it seems that the "why's" could go on forever, the parent will tire of the process or not have an understandable answer, in which case, the conversation is closed with, "Because I said so!"

As silly as it sounds, though, the child is following a very simple problem-solving approach. Ask a question about an issue. Get an answer. Ask a second question as to why the previous answer is true. Get another answer. Ask "why" a third time, and a fourth time, etc. The point is, if you ask "why" enough times, eventually you may find the root cause of the problem, and be able to address it with a corrective action.

In the lean manufacturing world, where systematic problem-solving is required to reduce the number of substandard products from a factory, the 5 Why's method should be used first to see if there is a simple answer for a tough issue.

Why were last month's sales so low?