Political Institutions, Economic Liberty, and the Great Divergence
研究了欧洲政治碎片化与政治创新（自治城市和国会）如何促进经济自由，进而加速城市增长，并发现西欧在1200年后城市间增长关联显著为正，且碎片化和国会区域关联最强。
I argue that Europe's political fragmentation interacted with her political innovations—self-governing cities and national parliaments—to facilitate “economic liberty,” which in turn unleashed faster and more inter-connected urban growth. Examining urban growth over the period 600–1800 ce throughout Eurasia, I show that inter-city growth correlations were positive and significant only in Western Europe after 1200 ce . Within Western Europe, I show that growth correlations were greatest in the most fragmented and parliamentary areas, individual cities became significantly more tied to urban growth when their realms became parliamentary, and spillover effects (due to competition between rulers) were significant.