Introduction

Let us start the discussion of multi-criteria evaluation by means of a simple everyday life example. Let us imagine staying in front of a shop and admiring a selection of jackets. What is the next step? Probably entering the shop and asking for the price. At this point, we have two possibilities: leaving the shop because we think the price is too high or accepting the price as reasonable. In the second case, we still need to choose the jacket we want from the original set (of, for example, ten jackets). We are therefore, probably going to try on the jackets and see which one suits us best aesthetically. Let us assume that we are then still undecided between four of them, although we definitely do not like the other six. How do we choose between the remaining four? Perhaps at this stage we will use the criterion of colour. Let us imagine we are then still undecided between two jackets. We will now look at the quality of the fabric and we may finally choose the one with the better quality.