Abstract
Power index analysis is very important in all group decision making processes. There is no better way how to evaluate the power to act of a decision maker than a priori power index.
The formal analysis of measuring sensitivity of the index are presented in the paper. Constant power partition of weight allocation space with respect to a given quota is defined.
Responses of the measures of power to changes of allocations of weights, quota and/or number of voters are considered. Proposed methods are base for algorithms of sensitivity analysis of a priori power indices.