Basic Tools for Process Improvement
4 CAUSE-AND-EFFECT DIAGRAM
How do we develop a Cause-and-Effect Diagram?
When you develop a Cause-and-Effect Diagram, you are constructing a structured,
pictorial display of a list of causes organized to show their relationship to a specific
effect. Viewgraph 3 shows the basic layout of a Cause-and-Effect Diagram. Notice
that the diagram has a cause side and an effect side. The steps for constructing and
analyzing a Cause-and-Effect Diagram are outlined below.
Step 1 - Identify and clearly define the outcome or EFFECT to be analyzed
(Viewgraph 4).
! Decide on the effect to be examined. Effects are stated as particular quality
characteristics, problems resulting from work, planning objectives, and the like.
! Use Operational Definitions. Develop an Operational Definition of the effect to
ensure that it is clearly understood.
! Remember, an effect may be positive (an objective) or negative (a problem),
depending upon the issue that’s being discussed.
> Using a positive effect which focuses on a desired outcome tends to foster
pride and ownership over productive areas. This may lead to an upbeat
atmosphere that encourages the participation of the group. When possible,
it is preferable to phrase the effect in positive terms.
> Focusing on a negative effect can sidetrack the team into justifying why the
problem occurred and placing blame. However, it is sometimes easier for
a team to focus on what causes a problem than what causes an excellent
outcome. While you should be cautious about the fallout that can result
from focusing on a negative effect, getting a team to concentrate on things
that can go wrong may foster a more relaxed atmosphere and sometimes
enhances group participation.
You must decide which approach will work best with your group.
NOTE: The EXAMPLE that is imbedded in the explanation of Cause-and-Effect
Diagram construction and analysis on the next few pages is based on a chart in
The Memory Jogger [Ref. 1, p. 28]. This diagram has been broken down into its
component parts and expanded to illustrate the construction steps. Using this
example, we will diagram the causes relating to a car’s getting poor gas mileage.