An index of power is proposed, based on the concept of the entropy of
information, which measures the distribution of power among decision m
akers who commit themselves at distinctive stages in the hierarchical
decision systems. The index is tested and is shown to work well with a
model of public decision-making in an indirect democracy. Moreover, i
t is shown that the entropy decreases monotonically in hierarchical an
d sequential decision systems. This property indicates support for the
applicability of the index.