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The IS–LM model, or Hicks–Hansen model, is a macroeconomic tool that shows the relationship between interest rates and real output, in the goods and services market and the money market (also known as the assets market). The intersection of the "investment–saving" (IS) and "liquidity preference–money supply" (LM) curves is the "general equilibrium" where there is simultaneous equilibrium in both markets. Two equivalent interpretations are possible: first, the IS–LM model explains changes in national income when the price level is fixed in the short-run; second, the IS–LM model shows why the aggregate demand curve shifts. Hence, this tool is sometimes used not only to analyse the fluctuations of the economy but also to find appropriate stabilisation policies. The model was developed by John Hicks in 1937,〔 and later extended by Alvin Hansen, as a mathematical representation of Keynesian macroeconomic theory. Between the 1940s and mid-1970s, it was the leading framework of macroeconomic analysis. While it has been largely absent from macroeconomic research ever since, it is still the backbone of many introductory macroeconomics textbooks. ==History== The IS/LM model was born at the econometric conference held in Oxford during September, 1936. Roy Harrod, John R. Hicks, and James Meade all presented papers describing mathematical models attempting to summarize John Maynard Keynes' ''General Theory of Employment, Interest, and Money''.〔 Hicks, who had seen a draft of Harrod's paper, invented the IS/LM model (originally using the abbreviation "LL", not "LM"). He later presented it in "Mr. Keynes and the Classics: A Suggested Interpretation". Hicks later agreed that the model missed important points of Keynesian theory, criticizing it as having very limited use beyond "a classroom gadget", and criticizing equilibrium methods generally: "When one turns to questions of policy, looking towards the future instead of the past, the use of equilibrium methods is still more suspect." The first problem was that it presents the real and monetary sectors as separate, something Keynes attempted to transcend. In addition, an equilibrium model ignores uncertainty—and that liquidity preference only makes sense in the presence of uncertainty "For there is no sense in liquidity, unless expectations are uncertain."〔 A shift in one of the IS or LM curves will cause a change in expectations, which shifts the other curve. Most modern macroeconomists see the IS/LM model as being—at best—a starting approximation for understanding the real world. Although generally accepted as being imperfect, the model is seen as a useful pedagogical tool for imparting an understanding of the questions that macroeconomists today attempt to answer through more nuanced approaches. As such, it is included in most undergraduate macroeconomics textbooks, but omitted from most graduate texts due to the current dominance of real business cycle and new Keynesian theories. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「IS–LM model」の詳細全文を読む スポンサード リンク
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