Keynesian economics

Keynesian economics ( /?ke?nzi?n/ kayn-zee-?n; also called Keynesianism and Keynesian theory) are the group of macroeconomic schools of thought based on the ideas of 20th-century economist John Maynard Keynes. Keynesian economists believe that, in the short run, productive activity is influenced by aggregate demand (total spending in the economy), and that aggregate demand does not necessarily equal aggregate supply (the total productive capacity of the economy). Instead, it is influenced by a host of factors and sometimes behaves erratically, affecting production, employment, and inflation.[1] Advocates of Keynesian economics argue that private sector decisions sometimes lead to inefficient macroeconomic outcomes which require active policy responses by the public sector, particularly monetary policy actions by the central bank and fiscal policy actions by the government to stabilize output over the business cycle.[2] The theories forming the basis of Keynesian economics were first presented by Keynes in his book, The General Theory of Employment, Interest and Money, published in 1936. Keynes contrasted his approach to the 'classical' (more commonly 'neoclassical') economics that preceded his book. The interpretations of Keynes that followed are contentious and several schools of thought claim his legacy. Keynesian economics advocates a mixed economy – predominantly private sector, but with a role for government intervention during recessions – and in the US served as the standard economic model during the later part of the Great Depression, World War II, and the post-war economic expansion (1945–1973), though it lost some influence following the stagflation of the 1970s.[3] The advent of the global financial crisis in 2008 has caused a resurgence in Keynesian thought Theory Prior to the publication of Keynes' General Theory, mainstream economic thought was that the economy existed in a state of general equilibrium, meaning that the economy naturally consumes whatever it produces because the needs of consumers are always greater than the capacity of the economy to satisfy those needs. This perception is reflected in Say's Law[5] and in the writing of David Ricardo,[6] which is that individuals produce so that they can either consume what they have manufactured or sell their output so that they can buy someone else's output. This perception rests upon the assumption that if a surplus of goods or services exists, they would naturally drop in price to the point where they would be consumed. Keynes' theory was significant because it overturned the mainstream thought of the time and brought about a greater awareness that problems such as unemployment are not a product of laziness, but the result of a structural inadequacy in the economic system. He argued that because there was no guarantee that the goods that individuals produce would be met with demand, unemployment was a natural consequence. He saw the economy as unable to maintain itself at full employment and believed that it was necessary for the government to step in and put under-utilised savings to work through government spending. Thus, according to Keynesian theory, some individually rational microeconomic-level actions such as not investing savings in the goods and services produced by the economy, if taken collectively by a large proportion of individuals and firms, can lead to outcomes wherein the economy operates below its potential output and growth rate. Prior to Keynes, a situation in which aggregate demand for goods and services did not meet supply was referred to by classical economists as a general glut, although there was disagreement among them as to whether a general glut was possible. Keynes argued that when a glut occurred, it was the over-reaction of producers and the laying off of workers that led to a fall in demand and perpetuated the problem. Keynesians therefore advocate an active stabilization policy to reduce the amplitude of the business cycle, which they rank among the most serious of economic problems. According to the theory, government spending can be used to increase aggregate demand, thus increasing economic activity, reducing unemployment and deflation. Keynes argued that the solution to the Great Depression was to stimulate the economy ("inducement to invest") through some combination of two approaches: A reduction in interest rates (monetary policy), and Government investment in infrastructure (fiscal policy). By reducing the interest rate at which the central bank lends money to commercial banks, the government sends a signal to commercial banks that they should do the same for their customers. Investment by government in infrastructure injects income into the economy by creating business opportunity, employment and demand and reversing the effects of the aforementioned imbalance.[7] Governments source the funding for this expenditure by borrowing funds from the economy through the issue of government bonds, and because government spending exceeds the amount of tax income that the government receives, this creates a fiscal deficit. To Keynes, excessive saving, i.e. saving beyond planned investment, was a serious problem, encouraging recession or even depression. Excessive saving results if investment falls, perhaps due to falling consumer demand, over-investment in earlier years, or pessimistic business expectations, and if saving does not immediately fall in step, the economy would decline. The classical economists argued that interest rates would fall due to the excess supply of "loanable funds". The first diagram, adapted from the only graph in The General Theory, shows this process. (For simplicity, other sources of the demand for or supply of funds are ignored here.) Assume that fixed investment in capital goods falls from "old I" to "new I" (step a). Second (step b), the resulting excess of saving causes interest-rate cuts, abolishing the excess supply: so again we have saving (S) equal to investment. The interest-rate (i) fall prevents that of production and employment.

Keynes had a complex argument against this laissez-faire response. The graph below summarizes his argument, assuming again that fixed investment falls (step A). First, saving does not fall much as interest rates fall, since the income and substitution effects of falling rates go in conflicting directions. Second, since planned fixed investment in plant and equipment is based mostly on long-term expectations of future profitability, that spending does not rise much as interest rates fall. So S and I are drawn as steep (inelastic) in the graph. Given the inelasticity of both demand and supply, a large interest-rate fall is needed to close the saving/investment gap. As drawn, this requires a negative interest rate at equilibrium (where the new I line would intersect the old S line). However, this negative interest rate is not necessary to Keynes's argument. Third, Keynes argued that saving and investment are not the main determinants of interest rates, especially in the short run. Instead, the supply of and the demand for the stock of money determine interest rates in the short run. (This is not drawn in the graph.) Neither changes quickly in response to excessive saving to allow fast interest-rate adjustment. Finally, Keynes suggested that, because of fear of capital losses on assets besides money, there may be a "liquidity trap" setting a floor under which interest rates cannot fall. While in this trap, interest rates are so low that any increase in money supply will cause bond-holders (fearing rises in interest rates and hence capital losses on their bonds) to sell their bonds to attain money (liquidity). In the diagram, the equilibrium suggested by the new I line and the old S line cannot be reached, so that excess saving persists. Some (such as Paul Krugman) see this latter kind of liquidity trap as prevailing in Japan in the 1990s. Most economists agree that nominal interest rates cannot fall below zero. However, some economists (particularly those from the Chicago school) reject the existence of a liquidity trap. Even if the liquidity trap does not exist, there is a fourth (perhaps most important) element to Keynes's critique. Saving involves not spending all of one's income. Thus, it means insufficient demand for business output, unless it is balanced by other sources of demand, such as fixed investment. Therefore, excessive saving corresponds to an unwanted accumulation of inventories, or what classical economists called a general glut.[10] This pile-up of unsold goods and materials encourages businesses to decrease both production and employment. This in turn lowers people's incomes—and saving, causing a leftward shift in the S line in the diagram (step B). For Keynes, the fall in income did most of the job by ending excessive saving and allowing the loanable funds market to attain equilibrium. Instead of interest-rate adjustment solving the problem, a recession does so. Thus in the diagram, the interest-rate change is small. Whereas the classical economists assumed that the level of output and income was constant and given at any one time (except for short-lived deviations), Keynes saw this as the key variable that adjusted to equate saving and investment. Finally, a recession undermines the business incentive to engage in fixed investment. With falling incomes and demand for products, the desired demand for factories and equipment (not to mention housing) will fall. This accelerator effect would shift the I line to the left again, a change not shown in the diagram above. This recreates the problem of excessive saving and encourages the recession to continue. In sum, to Keynes there is interaction between excess supplies in different markets, as unemployment in labour markets encourages excessive saving—and vice-versa. Rather than prices adjusting to attain equilibrium, the main story is one of quantity adjustment allowing recessions and possible attainment of underemployment equilibrium.