Just now, I heard my former student Joe Siegle give a sneak preview of a book that he has written with Morton Halperin and Michael Weinstein, The Democracy Advantage: How Democracies Promote Prosperity and Peace. The conventional wisdom among powerful experts holds that democracy arrives only at the end of a process of economic development. First, says Fareed Zakaria, a country must reach a per capita income of $6,000; then it can democratize. Below that level (allegedly), autocratic governments are better than democracies at marshalling resources, working for the long-term, suppressing conflicts, and thereby getting their countries to $6,000 per person.

Siegle et al. find that this is all thoroughly wrong. Among low-income countries over the last 40 years, democracies have grown as fast as autocracies. Most of the successful autocracies have been the “tigers” of East Asia (Singapore, Malaysia, and the like). If you exclude them from the sample, low-income democracies perform much better than autocracies. The data would favor democracies even more clearly if we had economic statistics from all the dictatorships. The worst tyrannies are very secretive and don’t release plausible development statistics, but clearly countries like North Korea would pull the autocracies’ average down if they were counted.

One of the reasons for democracies’ strong economic performance is their consistency. Compared to autocracies, they don’t collapse as often, and they don’t collapse as badly. Of the 80 worst cases (losses of GNP within a single year), only five have been democracies.

If one moves beyond GNP per capita or GNP growth, the other human development statistics favor democracies much more. For example, in poor countries, democratic government seems to confer about 9 extra years of life expectancy, compared to autocracies. And citizens of poor democracies are 40% more likely than citizens of poor autocracies to attend secondary school.