Migration response to an immigration shock: Evidence from Russia's aggression against Ukraine

Russia's attacks against Ukraine have triggered massive and unexpected migration movements. In this paper, I examine the impact of the inflow of Ukrainians that resulted from Russia's aggression in 2014 on local migration patterns in Poland. For identification, I use an instrumental variable approach drawing on unique historical data on the forced resettlement of Ukrainians in Poland after World War II. The results show that the regional inflow of immigrants decreases both internal and international out-migration of the Polish population. I provide supportive evidence that the decrease in out-migration is due to the upscaling of local labor markets.