Al Lindner, Fred Buller, Doug Stange, Dave Csanda, Ron Lindner, Bob Ripley, and Jan Eggers, Pike: An In-Fisherman Handbook of Strategies, 1983, In-Fisherman.

When a process goes out of control, employees strive to find the root causes. A "cause and effect diagram," as shown in Figure 2-4, can help pinpoint the source of the problem.

To use this approach, the problem-solving team starts with a problem. In this case, it is excessive variation in the test results of a pharmaceutical. By brainstorming, the team identifies all posible root causes.