Offshoring, Automation, Low-Skilled Immigration, and Labor Market Polarization
研究发现，仅考虑本土工人时就业极化现象消失，低技能移民解释了低技能就业增长，而离岸外包和自动化主要影响中等技能职业，低技能移民压低低技能工资并促使本土工人通过培训转向高技能职业。
We show that the observed polarization of employment toward the high- and low-skill occupations disappears when only native workers are considered. Instead, low-skilled immigration explains employment growth at the low tail of the skill distribution. Moreover, while employment rose, wages remained subdued in low-skill occupations. A data-disciplined structural model accounts for this evidence: Offshoring and automation negatively affect middle-skill occupations but enhance employment and wages for the high-skilled. Low-skill employment is sheltered from offshoring and automation, as it consists of manual, non-tradable services. However, low-skilled immigration depresses low-skill wages and encourages native workers to move into skilled occupations through training.