Sorting methods, in particular ELECTRE Tri methods, are widely used in Multiple Criteria Decision Aiding to deal with ordinal classification problems. Problems of this kind encountered in practice involve the evaluation of different alternatives (actions) on several evaluation criteria that are structured in a hierarchical way. In order to deal with a hierarchical structure of criteria in decision problems, Multiple Criteria Hierarchy Process (MCHP) has been recently proposed. In this paper, we apply the MCHP to the ELECTRE-Tri methods. In particular, we extend ELECTRE Tri-B, ELECTRE Tri-C and ELECTRE Tri-nC methods. We also adapt the MCHP concept to the case where interaction among evaluation criteria has either strengthening, or weakening, or antagonistic effect. Finally, we present an extension of the SRF method to determine the weights of criteria in case they are hierarchically structured. 
Multiple Criteria Hierarchy Process for ELECTRE Tri methods