New Estimates for Wage Rate Inequality Using the Employment Cost Index
利用就业成本指数衡量固定岗位的工资率变化，发现1980年代行业和职业群体的工资增长差异较大，但此后趋于一致，表明1990年代低工资工人相对中工资工人工资率的上升源于岗位结构变化，而非岗位内工资调整。
The Employment Cost Index measures the change in wage rates for a fixed set of jobs over time. The separate indices for industry and occupation groups grew at varying rates during the 1980s. However, their growth rates have been much more similar since then, which implies that the increase in the wage rates of low-wage workers relative to middlewage workers during the 1990s was due to changes in the mix of jobs. Had all workers remained in their jobs, the relative wage of low-wage to middle-wage workers would have remained constant.