Border Fencing, Migrant Flows, and Crossing Deaths

Using data from the US Customs and Border Protection and novel data on border fencing, we examine how the construction of border fencing under the Secure Fence Act influenced crossing decisions and the likelihood of migrant deaths. Apprehension data suggest that fence construction induced migrants to cross in unfenced sectors. Meanwhile, the average death rate rose nearly threefold in the sectors where the fence was not built. These results support our hypotheses that fence construction induced some migrants to cross in unfenced sectors, while others were diverted to cross in more dangerous locations within fenced sectors.