WHY HAVE AGGREGATE SKILLED HOURS BECOME SO CYCLICAL SINCE THE MID‐1980s?*
发现自1984年以来，美国熟练工时的波动性相对GDP几乎翻了三倍，而非熟练工时变化不大，并用资本-技能互补模型解释了约60%的增幅。
We document and discuss a dramatic change in the cyclical behavior of aggregate skilled hours since the mid‐1980s. Using CPS data for 1979:1–2003:4, we find that the volatility of skilled hours relative to the volatility of GDP has nearly tripled since 1984. In contrast, the cyclical properties of unskilled hours have remained essentially unchanged. We evaluate whether a simple supply/demand model for skilled and unskilled labor with capital‐skill complementarity in production can help explain this stylized fact. Our model accounts for about 60% of the observed increase in the relative volatility of skilled labor.