Matrix diagram

Matrix Diagram 
What is it and what does it do?
A Matrix Diagram (MD) is a tool that allows a team to identify the
presence and strengths of relationships between two or more lists of items.
It provides a compact way of representing many-to-many relationships of
varying strengths. An example matrix diagram is shown in figure 1.

Figure 1: An Example Matrix Diagram
Figure 1 shows, by the symbols, the presence of a relationship between the
items in list 1 and the items in list 2. The different symbols indicate the
strength of the relationship and an empty cell indicates no relationship.

Why do it?
Relationships between things are often complex (many-to-many) and
require us to think in more than one-dimension. The Matrix Diagram is a
simple tool that allows relatively complex situations to be analysed in a
simple straightforward way. They help us to expose interactions and
dependencies between things that help us to understand complex causal
relationships.

Where and when to use it?
A Matrix Diagram can be used where we wish to identify and assess the
strength of relationships between to or more lists of items. It is particularly
useful for examining the relationships between:
 a set of vague and un-measurable items with a set of precise and
measurable items (such as relating customer requirements to
technical requirements).
 two sets of items that are physically different (such as design
solutions to a set of technical requirements)
There are five basic types of Matrix Diagrams that allow for different
numbers of lists to be to be explored. The Types are:
 L-type
 T-type
 Y-type
 X-type
 C-type

 QFD Type (Quality Function Deployment)Also called: matrix, matrix chart

The matrix diagram shows the relationship between two, three or four groups of information. It also can give information about the relationship, such as its strength, the roles played by various individuals or measurements.

Six differently shaped matrices are possible: L, T, Y, X, C and roof–shaped, depending on how many groups must be compared.

When to Use Each Matrix Diagram Shape

Table 1 summarizes when to use each type of matrix. Also click on the links below to see an example of each type. In the examples, matrix axes have been shaded to emphasize the letter that gives each matrix its name.

• An L–shaped matrix relates two groups of items to each other (or one group to itself).
• A T–shaped matrix relates three groups of items: groups B and C are each related to A. Groups B and C are not related to each other. 
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• This L-shaped matrix summarizes customers’ requirements. The team placed numbers in the boxes to show numerical specifications and used check marks to show choice of packaging. The L-shaped matrix actually forms an upside-down L. This is the most basic and most common matrix format.
  
   Customer Requirements

  	Customer D	Customer M	Customer R	Customer T
  Purity %	> 99.2	> 99.2	> 99.4	> 99.0
  Trace metals (ppm)	< 5	—	< 10	< 25
  Water (ppm)	< 10	< 5	< 10	—
  Viscosity (cp)	20-35	20-30	10-50	15-35
  Color	< 10	< 10	< 15	< 10
  Drum
  Truck
  Railcar

   
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