# Matrix Designer  (Automatic Mode)

The Matrix Designer allows you to set the internal characteristics of the risk matrix such as the number of zones and the zone boundaries.

Note that the matrix size, i.e. the number of cells along each side, is set via the Datafile Setup form, and cannot be changed once you have defined any risk assessment scales.

The Matrix Designer (menu call Setup Menu/Risk Matrix) has two operating modes, automatic and manual. Automatic mode is easier to use but restricts you to a limited set of matrix configurations. Manual mode requires more experience to use but is completely unrestricted.

The Matrix Designer is shown here in automatic mode in a typical 5x5, 3-zone layout.

Risk Matrix Zones

In automatic mode, the Matrix Designer defines the risk matrix zones using the algorithm

Risk Severity  =  Probability Level  +  N * Impact

where probability level is an integer representing probability and N is a numerical constant. The value of N is controlled via the up/down arrows in the box immediately above the matrix on the Matrix Designer form.

A risk severity value is calculated for every value of impact and probability level. For example, if N = 2,  severity values from 3 to 15 will result for a 5x5 matrix. Matrix zones are then defined by dividing this range into equal, or nearly equal groups. In this case, the zone definitions are:

Red zone        12-15

Yellow zone      8-11

Green zone       3-7

resulting in the matrix shown here.

Risk Rank Values in Automatic Mode

Risk rank values are calculated by Mandrel in automatic mode by assigning severity values according to the risk severity algorithm given above, and then assigning rank based on severity. Where two or more elements have the same severity value, rank is assigned in order of impact value. You can view these rankings by checking the Show risk rank box, but you cannot modify them in automatic mode.

Probability Scale

You can divide the probability axis into equal probability intervals, e.g. 0%, 20%, 40%, etc, or into decade multiples, e.g. 0.1%, 1%, 10% etc.

Default Matrix

The default matrix built into Mandrel is a 3-zone matrix with zone boundaries defined by the risk severity algorithm with N = 2. If you modify the matrix, you can always return to the default configuration by clicking on the Default button.