On the Optimal Number of Representatives

We propose a normative theory of the number of representatives based on a stylized model of a representative democracy. We derive a simple formula, a "square-root theory" which gives the number of representatives in parliament as proportional to the square root of total population. Simple econometric tests of the formula on a sample of a 100 countries yield surprisingly good results. These results provide a benchmark for a discussion of the appropriateness of the number of representatives in some countries. It seems that the United States have too few representatives, while France and Italy have too many. The excess number of representatives matters: it is positively correlated with indicators of red tape, barriers to entrepreneurship and perceived corruption.