Getting the Most From Cause and Effect Diagrams

by Timothy J. Clark

Editor's Note: The following article expands on an idea briefly mentioned in the book Success Through Quality: Support Guide for the Journey to Continuous Improvement, written by Timothy J. Clark and published by ASQ Quality Press (item H1006).

The cause and effect diagram was developed by Kaoru Ishikawa in 1943 and is one of the seven basic tools of quality. The tool helps identify and document the causes and subcauses of a specific problem or effect (see Figure 1). The assumption is that if one or more causes of a problem are eliminated or reduced, then quality will be improved.

A cause and effect diagram can be enhanced, however, by following up with a responsibility matrix and an action planning matrix. A responsibility matrix identifies the degree of control process owners have over the cause of a particular problem and the action that can be taken to reduce or eliminate the problem. The action planning matrix acts as a final step for taking action and assessing results.

The responsibility matrix

The responsibility matrix identifies who within the system has ownership over the cause, as well as the degree of control that person has over eliminating or reducing the effects of the cause.

When developing a responsibility matrix, begin by listing the causes and provide a short description of each, including any subcauses. Next, identify the process owners and the degree
of control they have over each cause. Control can be broken down into three degrees: direct, some or little. Finally, document the action to be taken. A completed responsibility matrix using three of the causes listed in Figure 1 is provided in Table 1.

The planning matrix

Once responsibilities and actions are determined, the next step is to complete a planning matrix (see Table 2). This matrix includes the action to be taken and the expected result, the individual taking the action (who), when the action is to be completed and the necessary resources.

These matrices supplement the cause and effect diagram. They help demonstrate and communicate the interdependencies and degree of control among stakeholders, coordinate and align improvement actions, identify who will participate and illustrate that action can be taken despite the level of control.

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TIMOTHY J. CLARK is a systems accountant for the Department of Defense Finance and Accounting Service-Indianapolis Center. He earned his master's degree in public administration from Ball State University in Muncie, IN. Clark is a certified Koalaty Kid trainer, an ASQ certified quality auditor and an ASQ Senior Member.

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