Evaluating the quality of approximations to the non-dominated set

The growing interest in hard multiple objective combina tori l and non-linear problems resulted in a significant number of heuristic me thods aiming at generating sets of feasible solutions as approximations to the set of non -dominated solutions. The issue of evaluating these approximations is addressed. Such evaluatio ns re useful when performing experimental comparisons of different multiple objective heuristic algorithms, when defining stopping rules of multiple objective heuristic algorithms, and when adjusting parameters of heuristic algorithms to a given problem. A family of out performance relations that can be used to compare approximations under very weak assumptions about a decision-maker’s preferences is introduced. These outperformance relations define incomplete orders in the set of all approximations. It is shown that in order to co mpare approximations, which are incomparable according to the outperformance relations, much stronger assumptions about the decision-maker's preferences are necessary. A general f ramework that can be used to compare and evaluate approximations under the presence of various t ype of additional information is proposed. Some particular comparison and evaluation methods based on this framework are suggested. The proposed framework is also used to characteriz e some previously proposed evaluation methods.