中文摘要
本文研究移民对工资、国内迁移与福利的影响。我利用美国人口普查数据，估计了一个空间均衡模型，其中劳动力按技能水平、性别和出生身份（本国出生或外国出生）加以区分。劳动者对城市的偏好具有异质性。各城市在生产率水平、住房价格和宜人度方面存在差异。我利用估计得到的模型，评估若干移民政策的分配后果。结果表明，按技能筛选的移民政策会给低技能劳动者带来福利收益，但会给高技能劳动者带来福利损失。负面影响在已在当地的高技能移民中更大。国内迁移缓解了最初的负面影响，在住房供给缺乏弹性的城市尤为如此。然而，部分劳动者受到的负面工资影响会加剧。这是因为某一类型劳动者的外迁可能提高该类型劳动者的当地工资，同时降低具有互补特征的劳动者的当地工资。总体而言，移民的福利效应在城市之间以及城市内部均存在较大差异。此外，我利用该模型评估墨西哥与美国之间边境墙的福利效应。结果表明，其潜在收益明显低于拟议的建设成本。
Abstract
Abstract This article studies the impact of immigration on wages, internal migration, and welfare. Using U.S. Census data, I estimate a spatial equilibrium model where labour differs by skill level, gender, and nativity. Workers are heterogeneous in city preferences. Cities vary in productivity levels, housing prices, and amenities. I use the estimated model to assess the distributional consequences of several immigration policies. The results show that a skill selective immigration policy leads to welfare gains for low skill workers, but welfare losses for high skill workers. The negative impacts are more substantial among the incumbent high skill immigrants. Internal migration mitigates the initial negative impacts, particularity in cities where housing supplies are inelastic. However, the negative wage impacts on some workers intensify. This is because an out-migration of workers of a given type may raise the local wages for workers of that type, while reducing the local wages of workers with complementary characteristics. Overall, there are substantial variations in the welfare effects of immigration across and within cities. Further, I use the model to assess the welfare effects of the border wall between Mexico and the U.S. The results show that the potential benefits are significantly smaller than the proposed cost of construction.