  The quality of governance of institutions, corporations and countries depends
on the ability of efficient decision making within the respective boards or
cabinets. Opinion formation processes within groups are size dependent. It is
often argued - as now e.g. in the discussion of the future size of the European
Commission - that decision making bodies of a size beyond 20 become strongly
inefficient. We report empirical evidence that the performance of national
governments declines with increasing membership and undergoes a qualitative
change in behavior at a particular group size. We use recent UNDP, World Bank
and CIA data on overall government efficacy, i.e. stability, the quality of
policy formulation as well as human development indices of individual countries
and relate it to the country's cabinet size. We are able to understand our
findings through a simple physical model of opinion dynamics in groups.
