Problem-solving tools are powerful things. But not so powerful that they are immune to human error. Few things are.

Analogously, this is one reason why our school teachers strongly encouraged proofreading. You know—critically reading what you just wrote to ensure that it is clear, well-organized, flows logically, contains no misspelled words... so that no one thinks you’re a total idiot.

Well, the same type of proofreading reasoning applies to problem-solving. Two tools come to mind. One is 5 whys, and the other is cause-and-effect diagrams (aka fishbone or Ishikawa diagrams).

5 Whys

Many folks are familiar with Taiichi Ohno’s “famous” 5 why example. It can be found on page 17 of his classic book, Toyota Production System: Beyond Large-Scale Production (Productivity Press, 1988).

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