Slave Escape, Prices, and the Fugitive Slave Act of 1850
利用1850年逃亡奴隶法作为自然实验，研究该法如何影响美国南北各州奴隶价格，发现北部蓄奴州奴隶价格相对南部上涨高达35%，且逃亡风险降低。
This paper examines the spatial relationship among slave prices, escape, and slave owners’ property rights using the Fugitive Slave Act of 1850 as a natural experiment. The act reinforced slave owners’ property rights, but its effect diminished with distance to the North. Estimates suggest that prices in Northern slave states increased by up to 35 percent relative to Southern states because of the act. The paper’s findings are robust to changes in sample restrictions, spatial composition effects, and placebo tests on the act’s implementation date. The contention that the act had an effect on escape risk is supported by a reduction in rewards offered and the frequency of advertisements for runaways observed in newspaper advertisements from the time.