A two-grade approach to ranking interval data

Ranking decision for interval data is a very important issue in decision making analysis. In recent years, several ranking approaches based on dominance relations have been developed. In these approaches, a dominance degree and an entire dominance degree are employed. However, one cannot obtain the complete rank of objects. To address this problem, this work will propose a two-grade approach to ranking interval data. In this approach, we keep the ranking result induced by the entire dominance degree in the first grade, and then refine the objects that cannot be ranked through introducing a so-called entire directional distance index. An example and a real case are employed to verify the effectivity of the two-grade ranking approach proposed in this paper.