This page enables you to run the program called ipdirect to evaluate power indices using the fundamental definitions directly. The indices computed are those that measure what Felsenthal and Machover (1998) called I-power (power as influence) based on counting all possble voting outcomes or coalitions equally.
The program computes the following for each member:
References: Penrose (1946), Banzhaf (1965), Coleman (1971)
The algorithm ipdirect has the advantage that it is simple and gives exact values for the power indices. Its major disadvantage is that it has exponential time complexity because the computing time required doubles each time an extra member is added. In practice this means that it works well for small voting bodies but is realistically infeasible for n>30. The web implementation here will in practice only work for voting bodies with fewer than 26 members because of system restrictions.
data in the boxes below.