The 5 Why Questions, Like All Roads, Lead to Rome

Today Patrick Shumaker from Gemba forwarded a great example of asking “Why?” persistently until the root cause is found. Why are U.S. standard railroad gages 4 feet 8.5 inches? Rome. You can find the full story on this bulletin board.
The “ask why 5 times” approach is also great way to find one of the seven wastes, the waste of processing. Often very hard to spot, but very easy to eliminate once you do, the waste of processing is an otherwise good process that simply isn’t needed or does more than needed. Typically the process is done “because we’ve always done it that way” or because of a long-forgotten or long since changed requirement.
I ran into that recently when one part still had to go through a batch oven process while another one 20 feet away did not. After going through the 5 why questions it turned out that they knew the oven process was not necessary, but it would be too much hassle from their customer to get the specs changed… So they were smart enough to design this waste of processing out of new parts, but the cost of removing it from older parts was too high due to another waste of processing, paperwork approvals.

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