This paper identifies systematic performance differences between younger and older democracies: younger democracies are more corrupt
exhibit less rule of law, lower levels of bureaucratic quality, and lower secondary school enrollments
and spend more on public investment and government workers. Only one theory explains the effects of democratic age on the wide range of policy outcomes examined here-the inability of political competitors in younger democracies to make credible promises to citizens. This explanation, first advanced in Keefer and Vlaicu (2004), offers a concrete interpretation of what political institutionalization might mean, and why it is that young democracies frequently fail to become older and well-performing democracies. A variety of tests support this explanation against alternatives. The effect of democratic age remains large even after controlling for the possibilities that voters are less well-informed in young democracies, that young democracies have systematically different political and electoral institutions, or that young democracies exhibit more polarized societies.