Matrix Diagram

The Matrix Diagram is an analysis tool that facilitates the systematic analysis of the strengths of relationships between two or more sets of elements.  It consists of a table whose main rows and columns contain the elements being inter-related, with the rest of its cells containing symbols or numbers that denote the strengths of relationship between the elements. 

The elements being inter-related in a matrix diagram may be in the form of information, concepts, conditions, activities, or other intangible items, as well as physical things such as people, equipment, tools, and materials.

The matrix diagram can be used in almost all types of decision making that involves several options or alternatives, or is affected by several factors.  Examples of these include: 1) equal distribution of major and minor assignments among members of a given project; 2) selection of a process, equipment, or material for a given purpose; 3) identifying the most critical factors affecting a given problem area; 4) matching of tasks to objectives, etc. 

The elements belonging to the same row or column should have something in common, so that they comprise a set that represents something.  For instance, a matrix diagram that relates various reliability tests to various failure mechanisms might show in its main row industry-standard reliability tests and on its main column commonly-encountered failure mechanisms.

The strength of relationship between each reliability test and each failure mechanism may then be denoted on the cell where they intersect with a symbol or a number (say, 1-3, with 3 denoting the strongest relationship). Table 1 shows a simplified version of such a matrix diagram. This matrix diagram shows, for instance, that if one wants to check the reliability of a set of samples with respect to package cracking and ball lifting, then TCT should be the reliability test used instead of PCT or HTOL.

Table 1. A Matrix Diagram Relating Reliability Tests to Failure Mechanisms