Methods to compare coalition's prevention power derived from effectivity for social choice correspondence

This paper proposes methods to compare coalition prevention power based on effectivity for social choice correspondence. The proposed methods compares a pair of coalitions from the point of view how coalitions can lose coalition's effectivity for social choice correspondence by deviation. Examples which show how the proposed methods work are given in this paper. Some properties of the proposed methods and difference from existing comparison method, which is called blockability relation, are shown.