====== Evaluations ======
===== Must, should and can criteria =====
One way of prioritising criteria is to differentiate between must, should and can criteria:
  * Must requirement: fulfilment of this requirement is mandatory. Without it, the service makes no sense.
  * Target requirement: The fulfilment of this requirement is important
  * Optional requirement: The fulfilment of this requirement is desirable, but has no influence on whether the service is used. 
===== Decision matrix ===== 
A decision matrix helps when there are several alternatives for solving a problem. The alternative solutions are evaluated on the basis of meaningful criteria. A decision matrix can be weighted or unweighted. In a weighted matrix, the criteria are multiplied by certain factors to express their relative importance. The procedure for this method comprises the following steps: 
  - The question is defined. 
  - The alternatives are shown. 
  - The criteria are determined. 
  - The weighting factors are defined (optional). 
  - The criteria are evaluated. 
  - The variant with the most points is favoured. 


Below is an example of a weighted evaluation matrix with the weighting factors 1 (completely unimportant) to 5 points (very important) and the evaluation factors 1 (very poor) to 10 (very good).

^ Decision          ||||||
| Should I no longer run my applications in my own data centre but in a cloud?                                                                                                                  ||||||
|                                                                                                      |                 | **Use cloud services**                        ||**Use your own data centre**                        ||
| **Criteria**                                                                                        | **Weighting**  | **Rating**              | **Total criteria**  | **Evaluation**         | **Sum of criteria**  |
| Scalability             |               5 |                          8 |                   40 |                     5 |                   25 |
| Simplicity            |               4 |                          5 |                   20 |                    10 |                   40 |
| Cost saving        |               3 |                          8 |                   24 |                     6 |                   18 |
| Dependency set     |               4 |                          5 |                   20 |                     8 |                   32 |
| Internet access        |               5 |                         10 |                   50 |                     5 |                   25 |
| Data security          |               1 |                         10 |                   10 |                     1 |                    1 |
| **Total variant**                                                                                   |                 |                            |                  164 |                       |                  141 |
 
In this example, the "Use cloud services" variant is preferable.