Job Polarization and Structural Change
发现美国的工作极化现象早在1950年代就已开始，中工资工人就业和工资增长均落后于低高工资工人，并基于从制造业向服务业转移的结构变迁提出解释模型，成功匹配了过去50年的行业就业和相对工资变化。
We document that job polarization—contrary to the consensus— has started as early as the 1950s in the United States: middle-wage workers have been losing both in terms of employment and average wage growth compared to low- and high-wage workers. Given that polarization is a long-run phenomenon and closely linked to the shift from manufacturing to services, we propose a structural change driven explanation, where we explicitly model the sectoral choice of workers. Our simple model does remarkably well not only in matching the evolution of sectoral employment, but also of relative wages over the past 50 years.