Timing is everything: Short-run population impacts of immigration in US cities

We provide the first analysis of the short-run causal impact of immigrant inflows on native populations at the local labor market level. Using published statistics from the American Community Surveys of 2000–2010, we examine how immigrant inflow shocks to a metropolitan area affect native populations. We find that immigrant inflows are associated with increases in local native populations on an annual basis but that these OLS estimates are generally upward biased. Our IV results are purged of this bias, but we still find that an additional immigrant increases the low skill native population by 0.4–0.7 in the concurrent period. To explain this result, we show that immigrant inflows lead to declines in outflows of low skill natives from affected MSAs. This is most pronounced in MSAs from which relocation is arguably more costly, which may disproportionately affect the low skilled. We find short-run responses among high skill natives that are consistent with displacement. The decline in high skilled native populations is driven by high skilled immigrant inflows, and high skilled outflows increase from affected MSAs. We show that these short-run changes are obscured in specifications using longer-run population changes and conclude that the short-run impact of immigrants on native populations differs markedly from their longer-run impact.