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# 7.2.4 RELATIONSHIP DIAGRAMS

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The next step is to evaluate and classify the data. One of the best tools to

accomplish this task is a Relationship Diagram. The Relationship Diagram was

reportedly invented by P. Chen and presented in his article in 1976.3 The purpose

of the Relationship Diagram is to show the interrelationships between

causative factors that relate to a problem.

A Relationship Diagram, as shown in Figure 7-4, is one that shows connec-

F i g u r e 7 - 4 — R e l a t i o n s h i p D i a g r a m

tions or relationships between the elements of the diagram. In this case, the

elements are Issues.

The Relationship Diagram, in contrast to the Affinity Diagram, which only

shows logical groupings, helps map the logical relationships between the related

items uncovered in the Affinity Diagram. The Relationship Diagram shows

cause and effect relationships among many key elements. It can be used to

identify the causes of problems or to work backward from a desired outcome

to identify all of the causal factors that would need to exist to ensure the

achievement of an outcome. The Relationship Diagram doesn’t necessarily need

to follow the form of the ‘‘bubble’’ chart shown. A traditional organization

chart and a flow diagram are examples of other presentations of Relationship

Diagrams.

The process to be used is as follows:

1. State the problem or family under discussion—software defects, customer

retention, process steps, whatever.

2. Capture that problem or issue in a box, bubble, or whatever.

3. Begin a process of looking for ‘‘drivers’’; that is, functions or issues that

drive the issue being considered. You can also use the rationale of the

PERT Chart (see glossary) in considering ‘‘predecessors’’ for this part of

the process. In other words, you are looking for items that drive or must

be completed before the issue at hand.

4. Begin a process of looking for ‘‘drivens,’’ that is, functions or issues that

are being driven by the issue at hand. If you prefer, use the term ‘‘predecessors’’

for ‘‘drivers’’ and ‘‘successors’’ for ‘‘drivens.’’

5. When you have diagrammed the issue and have located all the ‘‘drivers’’

and ‘‘drivens’’ something will jump out at you. That bubble or square

that has ‘‘drivers’’ but no ‘‘drivens’’ is the primary issue whether that’s

the one you started with or not!

If you want or need to go beyond the simple relationships of one issue driving

another, consider the following:

The bubble is the issue.

The lines (arrows) connecting the bubbles are the actions.

The value of the line (arrow) is the magnitude.

The characteristics of the bubble are its attributes.

A veritable glut of information exists on Relationship Diagrams. Much of it

is Entity-Relationship Diagrams as a result of our software society. The source

of a lot of the information is the use and application of relational databases

such as Microsoft’s Access. Most written information regarding Relationship

Diagrams is in the form of articles rather than books.

Software used to support Relationship Diagrams is listed in Table 7-5.

T a b l e 7 - 5 — R e l a t i o n s h i p D i a g r a m S o f t w a r e

Tool Product Vendor

Relationship Diagrams

‘‘EDGE Programmer’’ Pacestar Software

‘‘SmartDraw’’ SmartDraw.com

Following is contact information for the companies listed in Table 7-5:

Pacestar Software

P.O. Box 51974

Phoenix, AZ 85076-1974

Phone: 480-893-3046

Fax: 413-480-0645

Web site: www.pacestar.com

E-mail: mail@pacestar.com

TEAMFLY

SmartDraw.com

10085 Carroll Canyon Road, Suite 220

San Diego, CA 92131

Phone: 858-549-0314

Order: 800-501-0314

Fax: 858-549-2830

Web site: www.smartdraw.com

E-mail: mail@smartdraw.com