Declining Volatility in the U.S. Automobile Industry
发现1980年代初美国汽车行业产出波动性下降，库存投资与销售协方差更负，生产调整从雇佣解雇转向工时变化，并用线性二次库存模型证明这些变化源于汽车销售持久性下降。
Dramatic changes in the volatility of output occurred in the U.S. auto industry in the early 1980s. Namely, output volatility declined, the covariance of inventory investment and sales grew more negative, and adjustments to production schedules, which in earlier decades stemmed primarily from plants hiring and laying off workers, were more often accomplished with changes in average hours per worker after the mid-1980s. Using a linear quadratic inventory model with intensive and extensive labor adjustments, we show how all of these changes could have stemmed from one underlying factor—a decline in the persistence of motor vehicle sales.