Cause and Effect Analysis

Cause and Effect Analysis is a method leading to the listing of all possible reasons and outcomes associated with a particular problem or situation. It is a group process directed at uncovering possible or probable causal factors and their manifestation. The process identifies how they are linked, but does not necessarily lead to the root cause, or the removal of the reason to stop the recurrence of the problem. The process usually reports its results on a cause-and-effect diagram.[1]

A cause-and-effect analysis stimulates and broadens thinking about potential or real causes and facilitates further examination of individual causes. Because everyone’s ideas can find a place on the diagram, a cause-and-effect analysis helps to generate consensus about causes. It can help to focus attention on the process where a problem is occurring and to allow for constructive use of facts revealed by reported events. However, it is important to remember that a cause-and-effect diagram is a structured way of expressing hypotheses about the causes of a problem or about why something is not happening as desired. It cannot replace empirical testing of these hypotheses: it does not tell which is the root cause, but rather possible causes.

There are two ways to graphically organize ideas for a cause-and-effect analysis. They vary in how potential causes are organized:
(a) by category: called a fishbone diagram (for its shape) or Ishikawa diagram (for the man who invented it), and,
(b) as a chain of causes: called a tree diagram.
The choice of method depends on the team’s needs. A fishbone diagram, organized around categories of cause, will help the team think about groups of causes, such as those that are staffing-related, resource-related, facility-related, etc. A tree diagram, however, will encourage team members to explore the chain of events or causes.[2]

See Also


Further Reading