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Our results show that Old World regions that were suitable for potato cultivation experienced disproportionately faster population and urbanization growth after the introduction of potatoes.The estimates are extremely robust to a variety of sensitivity checks, including the omission of outliers and influential observations, the omission of Western Europe, the inclusion of the countries north of Mezzo America, and the inclusion of a host of additional control variables.
The magnitudes of our estimates are also interesting. One way to measure the estimated effectsis to ask how much of the average difference in population or urbanization levels (or their growth rates) between the pre-potato adoption period (1000–1700) and the post-adoption period (1700–1900) is explained by the introduction of the potato. Doing this calculation, our baseline estimates suggest that the potato accounts for 12% of the increase in population, 22% of the increase in population growth, 47% of the increase in urbanization, and 50% of the increase in urbanization growth.
— Nathan Nunn and Nancy Qian, “The Potato’s Contribution to Population and Urbanization: Evidence from an Historical Experiment”
