Matrix zones provide a fairly crude method of characterizing risk severity. This may be sufficient for some purposes, particularly if there are only a few identified risks. However, if there are a large number of risks in the system it can often be useful to have a finer method of classifying risk severity. This is provided by risk rank.
Each cell in the matrix is given a unique number known as its rank. The greater the severity of a risk the numerically smaller is its rank value, and vice versa. The cell at the top right hand corner of the matrix always has the value 1 and the cell at the bottom left hand corner always has the value M2 where M is the matrix size, i.e. the number of cells per axis. Intermediate cells are given appropriate intermediate values. A typical set of risk rank values is shown below for a 5x5 matrix.
Risk rank is, in effect, a means of identifying individual elements in the risk matrix. Whereas risk matrix zones divide the matrix up into blocks of individual elements, risk rank enables you to identify an individual element, since every element has its own numerical value.
Mandrel will provide a default set of rank values for any matrix configuration. However, you can modify these using the Matrix Designer.