One book that tries to quantify along several dimensions is "Democracy: The God that Failed: The Economics and Politics of Monarchy, Democracy, and Natural Orde

One book that tries to quantify along several dimensions is "Democracy: The God that Failed: The Economics and Politics of Monarchy, Democracy, and Natural Order" by Hans-Hermann Hoppe. Here's my notes from a related talk he gave on the subject: http://library.mises.org/media/The%20Costs%20of%20War/World%20War%20I%20as%20the%20End%20of%20Civilization%20Hans-Hermann%20Hoppe.mp3 http://library.mises.org/media/The%20Costs%20of%20War/World%... "in europe, during monarchy taxes were 3-5%, during democracy 25%. during monarchy debt was paid down during peace time, democracies increase debt during war and peace. during monarchy, price level fell century after century, and in democracy price level has risen. in monarchy interest rates fell, in democracy interest rates have risen. in monarchy money supply grew modestly (6x in century), in democracy it's grown enormously (1000x in century). govt gdp expenditures are much higher under democracy than monarchy. very little redistribution of wealth under monarchy. very little interference. very few new laws. most wars are limited to territory under dispute often bc of inheritance/marriage."