Partial Order Concepts in Ranking Environmental Chemicals

Abstract

With the discussion around REACH the interest in ranking of chemicals is increased. In this paper we take a statistical point of view in evaluation and ranking of chemicals. The data matrix with relevant properties of the chemicals plays the central role. Its evaluation is performed by simple concepts of partial order (Hasse diagram technique (HDT)). Several extensions are discussed: First the concept of METEOR (METhod of Evaluation by ORder Theory), then the approach by fuzzy concepts, combined with partial order, and finally the DLPO-concept (Double Layer Partial Orders). DLPO is a novel method where attributes are themselves combined by partial order. The main idea is to avoid the bias due to a functional combination of attributes (for example by weighted sums as in METEOR). Whereas HDT does not need any information beyond the data matrix, all other methods discussed so far, need additional knowledge.