The Unassuming Economist

From a new CEP Discussion Paper:

“The US suffers from large regional disparities in employment-population ratios (from here on, “employment rates”) which have persisted for many decades (Kline and Moretti, 2013; Amior and Manning, 2018). Concern has grown about these inequities in light of the Great Recession and a secular decline in manufacturing employment (Kroft and Pope, 2014; Acemoglu et al., 2016), whose impact has been heavily concentrated geographically (Moretti, 2012; Autor, Dorn and Hanson, 2013). In principle, these disparities should be eliminated by regional mobility, but this has itself been in secular decline in recent decades (Molloy, Smith and Wozniak, 2011; Dao, Furceri and Loungani, 2017; Kaplan and Schulhofer-Wohl, 2017).

In the face of these challenges, it has famously been argued that foreign migration offers a remedy. Borjas (2001) claims that new immigrants “grease the wheels” of the labor market: given they have already incurred the fixed cost of moving, they are very responsive to regional differences in economic opportunity – and therefore accelerate local population adjustment.1 And in groundbreaking work on the Great Recession period, Cadena and Kovak (2016) argue further that foreign-born workers (or at least low skilled Mexicans) continue to “grease the wheels” even some years after arrival. In terms of policy, if migrants are indeed regionally flexible, forcibly dispersing them within receiving countries may actually hurt natives as well as the migrants themselves. Basso, Peri and Rahman (2017) have extended the hypothesis beyond geography: they find that immigration attenuates the impact of technical change on local skill differentials.

I revisit the original question of geographical adjustment using decadal US data spanning 722 commuting zones (CZs) and 50 years – and using an empirical model which explicitly accounts for dynamic adjustment. Remarkably, I find that foreign migrants (and specifically new arrivals) account for around half of the average population response to local demand shocks. But in areas better supplied by new migrants, population growth is not significantly larger nor more responsive to these shocks. I claim that foreign migration crowds out the contribution from internal mobility that would have materialized in the counterfactual. This is not to say that natives gain little from the contribution of foreign migration. As I argue below, undercoverage of unauthorized migrants in the census may overstate the crowding out effect – and understate the foreign contribution to adjustment. And in any case, conditional on the overall level of immigration, a regionally flexible migrant workforce may save natives from incurring potentially steep moving costs themselves. As Molloy, Smith and Wozniak (2017) suggest, this may in principle shed a more positive light on the decline in regional mobility since the 1980s.”