PMBOK (2004 3rd 英) P186 质量规划工具中提到了Matrix Diagram但是没有具体解释，补充如下

When to use it

• Use it when comparing two lists to understand the many-to-many relationship between them (it is not useful if there is a simple one-to-one relationship).
• Use it to determine the strength of the relationship between either single pairs of items or a single item and another complete list.
• Use it when the second list is generated as a result of the first list, to determine the success of that generation process. For example, customer requirements versus design specifications.

side-by-side table 适合表示 one-to-one 关系，但是对many-to-many关系就很困难



Matrix  diagram可以显身手了



这篇文章有详细的解释和示例 http://syque.com/quality_tools/toolbook/Matrix/matrix.htm

he Matrix Diagram is used to identify the relationship between pairs of lists.

• When to use it: Situations when it is useful.
• How to understand it : Details of how it works.
• Examples : Some examples of usage.
• How to do it : Step-by-step instructions on using it.
• Practical variations : Variants and variation.