宏观经济学课件

– Useful in understanding economy over long-run
• While Keynes’s ideas and their further development help us understand economic fluctuations—movements in output around its long-run trend
• Polices that can help us smooth out economic fluctuations may prove harmful to growth in the long-run
– While policies that promise a high rate of growth might require us to put up with more severe fluctuations in short-run
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Macroeconomic Models: Classical
Verses Keynesian
• Keynesian ideas became increasingly popular in universities and government agencies during 1940s and 1950s
The Classical Long-Run Model
ECONOMICS: Principles and Applications 3e HALL & LIEBERMAN © 2005 Thomson Business and Professional Publishing
Slides by: John & Pamela Hall
– Over periods of several years or longer, economy performs rather well
• If we think in terms of decades rather than years or quarters, business cycle fades in significance
The Classical Long-Run Model
• Economists sometimes disagree with each other • Actually much more agreement exists among
economists than there appears to be • Once distinction between long-run and short-run
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Macroeconomic Models: Classical Verses Keynesian
• Classical model, developed by economists in 19th and early 20th centuries, was an attempt to explain a key observation about economy
• In the classical view, this behavior is no accident
– Powerful forces are at work that drive economy towards full employment
• An important group of macroeconomists continues to believe that classical model is useful even in shorter run
• In 1936, in midst of Great Depression, British economist John Maynard Keynes offered an explanation for economy’s poor performance
– Argued that, while classical model might explain economy’s operation in long-run, long-run could be a very long time in arriving
– Something about which economists sometimes do disagree
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The cal Long-Run Model
• Ideally, we would like our economy to do well in both long-run and short-run
– Unfortunately, there is often a trade-off between these two goals
• Doing better in short-run can require some sacrifice of long-run goals, and vice versa
• Classical model is still important
– In recent decades there has been an active counterrevolution against Keynes’s approach to understanding the macroeconomy
becomes clear
– Many apparent disagreements among macroeconomists dissolve
• If no time horizon is specified, however, an economist is likely to focus on horizon he or she feels is most important
– By mid-1960s, entire profession had been won over
• Macroeconomics was Keynesian economics
– Classical model was removed from virtually all introductory economics textbooks