Crop Yield and Democracy
研究发现作物产量与民主程度呈倒U型关系，基于147个国家、186个前殖民社会和美国各州的数据，该关系具有高度持续性。
How does the historical legacy of agriculture affect democratic traditions in contemporary societies? This paper provides empirical evidence that inherent crop yield and democracy exhibit an inverted U-shaped relationship. This finding is supported by cross-country data from up to 147 countries, 186 pre-colonial societies, and the U.S. states. The relationship thus exhibits a highly persistent pattern. Crop yield is measured by kilocalories per hectare per year under rain-fed conditions, which has the advantage of being highly exogenous. The hump-shaped relationship holds up to a battery of robustness tests.