What have we learned from empirical studies of unemployment and turnover
回顾了关于失业率上升的实证研究，指出失业集中在低技能男性中，需求下降是主因，且失业对收入有持久影响。
Unemployment reminds economists that we have a lot to be modest about. Twenty years ago, Robert Hall (1972) asked Why Is the Unemployment Rate so High at Full Employment? At the time Hall wrote, male unemployment in the United States had risen to 3.5 percent, and it would peak at 4.4 percent in the recession of 1971. Since then, every cyclical low of unemployment has exceeded the one before it; the end of the 1980's expansion reduced unemployment to about 4.5 percent, and unemployment peaked at 7.4 percent of the labor force in the recession that just ended. The natural rate of unemployment has evidently risen through time, which led Lawrence Summers (1986) to place a modifier in Hall's question: Why Is the Unemployment Rate So Very High...? In what follows I pose three questions about the causes and consequences of rising joblessness. First, who are the unemployed? I will show that unemployment and nonparticipation are heavily concentrated among the least skilled and, more importantly, that virtually all of the long-term increase in joblessness occurs among low-wage men. Unemployment and nonparticipation among highly skilled men are unchanged since the 1960's. Second, what factors have caused jobless time to rise? There are many theories, including changes in labor-force demographics, social programs that discourage employment, and changes in the amount of frictional unemployment caused by sectoral shifts. None of these is consistent with the evidence, which points instead to a secular decline in the demand for lessskilled workers. The data also cast doubt on nonmarket-clearing models of rising unemployment. Wages are demonstrably flexible in the long run, and they have fallen dramatically among the unskilled, whose jobless rates have risen. Third, what happens to the unemployed? In contrast to the view that unemployment spells cause transitory reductions in income, recent evidence indicates that job losses have substantial and permanent effects on earning power. Many of the unskilled who are unemployed or out of the labor force appear to have been high-wage workers whose specialized skills have become obsolete.