《宏观经济学-刘雅南课件》chap13 总供给.ppt

* * 内容提要 3. 如何形成通货膨胀预期 适应性预期 取决于近期观察到的通货膨胀 通货膨胀惯性 理性预期 取决于所有可以获得的信息 反通胀可以是无痛苦的 CHAPTER 13 Aggregate Supply slide * 内容提要 4.自然率假说和滞后作用 自然率假说 表明总需求的波动对产出和就业只有短期影响 滞后作用 表明总需求对产出和就业会产生持久的影响 CHAPTER 13 Aggregate Supply slide * * * * If you don’t like the appearance of the term “monopolistic competition” in this slide, just change the parenthetical comment to “(i.e. firms have some market power)” or something to that effect. * * * * * * * * The following is not in the text, but you and your students may find it worthwhile: There are good reasons to believe that the SRAS curve is bow-shaped in the real world; that is, the curve is steeper at high levels of output than at low levels of output. And there are good reasons why we should care about this. Why the SRAS curve is bow-shaped: At low levels of output, there are lots of unutilized and under-utilized resources available, so it is not terribly costly for firms to increase output, and therefore firms do not require a big increase in prices to make them willing to increase output by a given amount. In contrast, at very high levels of output, when unemployment is below the natural rate and capital is being used at higher than normal intensity levels, it is relatively costly for firms to increase output further. Hence, a larger increase in prices is required to make firms willing to increase their output. Why the curvature matters: When policymakers increase aggregate demand, output rises (good) and prices rise (not good). An important question arises: how much of the bad thing (price increases) must we tolerate to get some of the good thing (an increase output)? The answer depends on how steep the SRAS curve is. When President Reagan cut taxes in the early 1980s, the economy was just coming out of a severe recession, and was on the flatter part of the SRAS curve; hence, the tax cuts affected output a lot and inflation very little. In contrast, when the current President Bush proposed huge tax cuts dur