Jason Richwine, CIS, April 28, 2020
Last week the Cato Institute’s Alex Nowrasteh and Andrew Forrester published a self-defeating analysis of how immigration influences the spread of COVID-19 in the United States. After controlling for population density and state-level variation, they found no relationship at the county level between the foreign-born share of the population and the rate of viral infections and deaths. Their model shows that population density, not the foreign-born share, seems to have a strong association with the virus. Therefore, the authors conclude that immigration has not accelerated viral spread in the United States.
Their analysis is an own-goal (to borrow a soccer term), for the simple reason that immigration increases population density. Unless immigration somehow causes a major decrease in childbearing or life expectancy among natives, it’s true almost by definition that more immigration means more residents per square mile. (Immigration has added 43 million people to the United States since 1990, and none have created any new land!) Therefore, if we take the Nowrasteh-Forrester model seriously, then the virus would have spread less quickly in the United States if we had had lower levels of immigration. Similarly, accepting more immigrants will cause the virus to spread faster than it otherwise would.