At this point, we have identified and characterized both the decision-maker and all available alternatives. We will now focus on the assumptions about the rules used by the decision-maker to come up with the actual choice. Different sets of assumptions can be considered, that leads to different family of models. We will describe here three theories on decision rules, and the corresponding models. The neoclassical economic theory, described in Section 2.4.1, introduces the concept of utility. The Luce model (Section 2.4.2) and the random utility models (introduced in Section 2.4.3 and developed in Section 3) are designed to capture uncertainty.