The Cause and Effect Diagram has been around for over 50 years as a tool to help us organize potential root causes in our problem solving. Also called the fishbone diagram or Ishikawa Diagram, this tool is simple and effective when used properly. This is were I commonly find mistakes, this tool is not always used properly.
But creating this diagram is so easy, how could anybody possibly get it wrong? Well, not so much wrong as misguided in use that limits the effectiveness of the tool.
The most popular mistake is with the Manpower branch. Because we see a main branch dedicated to manpower, our problem solving mentality starts searching for "Who" to blame for the problem. Many times, we seek to blame someone for the problem due to lack of training, lack of experience or even worse lack of good sense.
Don't fall in this easy trap. Improve your diagram by digging deeper to link this manpower branch to the other branches-method, machine and material. If you stop at "Who", you are not at a potential root cause!
The second most popular mistake I have seen is limiting the manpower branch to just the employee. Why not include management in the manpower branch? Management plays a bigger role than the employee in practically all processes. It would make more sense to look at the role of management in relation to the problem.
In fact, to improve your diagram just add a management branch. Boy, won't that get some attention! NOTE: Even with a management branch, remember this is not a blame game so don't stop at "Who".
The other common misuse is not to add layered sub-branches. You must go beyond the surface questions to see the potential root causes. Without adding additional sub-branches to make us drill down, we just end up looking at symptoms of the problem.
Try these improvements on your Cause and Effect diagram to see if it helps in your next problem solving session.