School of Economics and Finance

No. 888: Horizontal and Vertical Polarization: Task-Specific Technological Change in a Multi-Sector Economy

Sang Yoon (Tim) Lee , Queen Mary University of London and CEPR
Yongseok Shin , Washington University in St. Louis, Federal Reserve Bank of St. Louis and NBER

July 2, 2019

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We construct a multi-layer model of skills, occupations, and sectors. Technological progress among middle-skill occupations raises the employment shares and relative wages of lower- and higher-skill occupations (horizontal polarization), and those of managers over workers (vertical polarization). Polarization is faster within sectors that rely more on middle-skill workers, endogenously boosting their TFP. This shrinks their employment and output shares (structural change) if sector outputs are complementary. We empirically validate our theoretical predictions, and show that task-specific technological progress, which was faster for routine-manual tasks and slower for interpersonal tasks, played a major role in transforming the U.S. economy since 1980.

J.E.L classification codes: J24, J31, L16, O14, O33

Keywords:job polarization, structural change, wage inequality