宏观经济学---曼昆chap06.ppt

* * * * * Sometimes the unemployment caused by sectoral shifts is severe. Due to increasing imports of cheaper foreign-made textiles (particularly since the expiration in 2005 of long-standing quotas on textiles from China), the U.S. textile industry has been in decline for years. Tens of thousands of workers in this industry have lost jobs. Many of these workers are in their 50s and have worked in this industry for decades. Such workers are unlikely to have the skills necessary to get jobs available in newly booming industries, and they are less likely to invest in the acquisition of the necessary skills for these jobs. Hence, such workers are at greater risk for becoming “discouraged workers.” * All figures are industry shares in U.S. GDP. “Other industry” includes construction, mining, electricity, water, and gas. From 1960 to 2000, there are huge changes in all four categories. Manufacturing falls by about a third. Even the “tiny” category of agriculture drops by nearly two-thirds:from 4.2% to 1.6% of GDP. These changes represent HUGE structural shifts, which vastly alter the kinds of jobs in demand. Source: World Development Indicators, World Bank. * Most of the examples on this and the previous slides are big changes that have occurred over many years. These examples give students a good idea of what sectoral shifts are. Perhaps more important for the natural rate, though, are the many smaller changes that occur more frequently. Ours is a dynamic economy: the structure of demand is shifting almost continuously, due to changes in preferences, technology, and the location of production. As a result, there is a near-continual flow of newly frictionally unemployed workers. Sectoral shifts are distinct from recessions (which also cause unemployment). In recessions, there is a general fall in demand across industries, and the unemployment that results is cyclical. Sectoral shifts, though, are changes in the composition of de