Ordinal Measurement for Decision Aid: a Conceptual Framework an Research Agenda

It happens more and more often in decision aiding situations to be faced with ordinal or nominal information concerning the alternatives that are considered by a client/decision maker (hereafter we will use the term decision maker DM). By the term ordinal or nominal information we intend the fact that evaluation on attributes, descriptors, indexes, criteria etc. may be expressed on ordinal or nominal scales which, although may allow a numerical representation, do not allow the usual manipulations on numbers since they could be meaningless.