Keynesian economics seeks to provide solutions to what some consider failures of laissez-faire economic liberalism, which advocates that markets and the private sector operate best without state intervention. The theories forming the basis of Keynesian economics were first presented in The General Theory of Employment, Interest and Money, published in 1936.

In Keynes's theory, some micro-level actions of individuals and firms can lead to aggregate macroeconomic outcomes in which the economy operates below its potential output and growth. Many classical economists had believed in Say's Law, that supply creates its own demand, so that a "general glut" would therefore be impossible. Keynes contended that aggregate demand for goods might be insufficient during economic downturns, leading to unnecessarily high unemployment and losses of potential output. Keynes argued that government policies could be used to increase aggregate demand, thus increasing economic activity and reducing high unemployment and deflation. Keynes's macroeconomic theories were a response to mass unemployment in 1920s Britain and in 1930s America.

Keynes argued that the solution to depression was to stimulate the economy ("inducement to invest") through some combination of two approaches :

* a reduction in interest rates.
* Government investment in infrastructure - the injection of income results in more spending in the general economy, which in turn stimulates more production and investment involving still more income and spending and so forth. The initial stimulation starts a cascade of events, whose total increase in economic activity is a multiple of the original investment.[1]

A central conclusion of Keynesian economics is that in some situations, no strong automatic mechanism moves output and employment towards full employment levels. This conclusion conflicts with economic approaches that assume a general tendency towards an equilibrium. In the 'neoclassical synthesis', which combines Keynesian macro concepts with a micro foundation, the conditions of General equilibrium allow for price adjustment to achieve this goal.

The New Classical Macroeconomics movement, which began in the late 1960s and early 1970s, criticized Keynesian theories, while "New Keynesian" economics have sought to base Keynes's idea on more rigorous theoretical foundations.

More broadly, Keynes saw his as a general theory, in which utilization of resources could be high or low, whereas previous economics focused on the particular case of full utilization.

Keynes sought to distinguish his theories from "classical economics," by which he meant the economic theories of David Ricardo and his followers, including John Stuart Mill, Alfred Marshall, F.Y. Edgeworth, and A. Cecil Pigou. A central tenet of the classical view, known as Say's law, states that “supply creates its own demand.” Say's Law can be interpreted in two ways. First, the claim that the total value of output is equal to the sum of income earned in production is a result of a national income accounting identity, and is therefore indisputable. A second and stronger claim, however, that the "costs of output are always covered in the aggregate by the sale-proceeds resulting from demand" depends on how consumption and saving are linked to production and investment. In particular, Keynes argued that the second, strong form of Say's Law only holds if increases in individual savings exactly match an increase in aggregate investment. (cf. General Theory, Ch.1,2)

Keynes sought to develop a theory that would explain determinants of savings, consumption, investment and production. In that theory, the interaction of aggregate demand and aggregate supply determines the level of output and employment in the economy.

Because of what he considered the failure of the “Classical Theory” in the 1930s, Keynes firmly objects its main theory—adjustments in prices would automatically make demand tend to the full employment level.

Neo-classical theory supports that the two main costs that shift demand and supply are labor and money. Through the distribution of the monetary policy, demand and supply can be adjusted. If there were more labor than demand for it, wages would fall until hiring began again. If there was too much saving, and not enough consumption, then interest rates would fall until people either cut their savings rate or started borrowing.

Wages and spending

During the Great Depression, the classical theory defined economic collapse as simply a lost incentive to produce. Mass unemployment was caused only by high and rigid real wages.

To Keynes, the determination of wages is more complicated. First, he argued that it is not real but nominal wages that are set in negotiations between employers and workers, as opposed to a barter relationship. First, nominal wage cuts would be difficult to put into effect because of laws and wage contracts. Even classical economists admitted that these exist; unlike Keynes, they advocated abolishing minimum wages, unions, and long-term contracts, increasing labor-market flexibility. However, to Keynes, people will resist nominal wage reductions, even without unions, until they see other wages falling and a general fall of prices.

He also argued that to boost employment, real wages had to go down: nominal wages would have to fall more than prices. However, doing so would reduce consumer demand, so that the aggregate demand for goods would drop. This would in turn reduce business sales revenues and expected profits. Investment in new plants and equipment—perhaps already discouraged by previous excesses—would then become more risky, less likely. Instead of raising business expectations, wage cuts could make matters much worse.

Further, if wages and prices were falling, people would start to expect them to fall. This could make the economy spiral downward as those who had money would simply wait as falling prices made it more valuable—rather than spending. As Irving Fisher argued in 1933, in his Debt-Deflation Theory of Great Depressions, deflation (falling prices) can make a depression deeper as falling prices and wages made pre-existing nominal debts more valuable in real terms. Excessive saving
Classics on Saving and Investment.

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 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 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 mostly based 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.
Keynes on Saving and Investment.

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 change quickly in response to excessive saving to allow fast interest-rate adjustment.

Finally, because of fear of capital losses on assets besides money, Keynes suggested that there may be a "liquidity trap" setting a floor under which interest rates cannot fall. (In this trap, bond-holders, fearing rises in interest rates (because rates are so low), fear capital losses on their bonds and thus try to sell them to attain money (liquidity).) Even economists who reject this liquidity trap now realize that nominal interest rates cannot fall below zero (or slightly higher). 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.

Even if this "trap" does not exist, there is a fourth element to Keynes's critique (perhaps the most important part). Saving involves not spending all of one's income. It thus means insufficient demand for business output, unless it is balanced by other sources of demand, such as fixed investment. Thus, excessive saving corresponds to an unwanted accumulation of inventories, or what classical economists called a general glut[2]. 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 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 labor 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.

Active fiscal policy

As noted, the classicals wanted to balance the government budget. To Keynes, this would exacerbate the underlying problem: following either policy would raise saving (broadly defined) and thus lower the demand for both products and labor. For example, Keynesians see Herbert Hoover's June 1932 tax increase as making the Depression worse[citation needed].

Keynes's ideas influenced Franklin D. Roosevelt's view that insufficient buying-power caused the Depression. During his presidency, Roosevelt adopted some aspects of Keynesian economics, especially after 1937, when, in the depths of the Depression, the United States suffered from recession yet again following fiscal contraction. Something similar to Keynesian expansionary policies had been applied earlier by both social-democratic Sweden, and Nazi Germany[citation needed]. But to many the true success of Keynesian policy can be seen at the onset of World War II, which provided a kick to the world economy, removed uncertainty, and forced the rebuilding of destroyed capital. Keynesian ideas became almost official in social-democratic Europe after the war and in the U.S. in the 1960s.

Keynes's theory suggested that active government policy could be effective in managing the economy. Rather than seeing unbalanced government budgets as wrong, Keynes advocated what has been called countercyclical fiscal policies, that is policies which acted against the tide of the business cycle: deficit spending when a nation's economy suffers from recession or when recovery is long-delayed and unemployment is persistently high—and the suppression of inflation in boom times by either increasing taxes or cutting back on government outlays. He argued that governments should solve problems in the short run rather than waiting for market forces to do it in the long run, because "in the long run, we are all dead." [2]

This contrasted with the classical and neoclassical economic analysis of fiscal policy. Fiscal stimulus (deficit spending) could actuate production. But to these schools, there was no reason to believe that this stimulation would outrun the side-effects that "crowd out" private investment: first, it would increase the demand for labor and raise wages, hurting profitability; Second, a government deficit increases the stock of government bonds, reducing their market price and encouraging high interest rates, making it more expensive for business to finance fixed investment. Thus, efforts to stimulate the economy would be self-defeating.

The Keynesian response is that such fiscal policy is only appropriate when unemployment is persistently high, above what is now termed the Non-Accelerating Inflation Rate of Unemployment, or "NAIRU". In that case, crowding out is minimal. Further, private investment can be "crowded in": fiscal stimulus raises the market for business output, raising cash flow and profitability, spurring business optimism. To Keynes, this accelerator effect meant that government and business could be complements rather than substitutes in this situation. Second, as the stimulus occurs, gross domestic product rises, raising the amount of saving, helping to finance the increase in fixed investment. Finally, government outlays need not always be wasteful: government investment in public goods that will not be provided by profit-seekers will encourage the private sector's growth. That is, government spending on such things as basic research, public health, education, and infrastructure could help the long-term growth of potential output.

Invoking public choice theory, classical and neoclassical economists doubt that the government will ever be this beneficial and suggest that its policies will typically be dominated by special interest groups, including the government bureaucracy. Thus, they use their political theory to reject Keynes' economic theory.

A Keynesian economist might point out that classical and neoclassical theory does not explain why firms acting as "special interests" to influence government policy are assumed to produce a negative outcome, while those same firms acting with the same motivations outside of the government are supposed to produce positive outcomes.

In Keynes' theory, there must be significant slack in the labor market before fiscal expansion is justified. Both conservative and some neoliberal economists question this assumption, unless labor unions or the government "meddle" in the free market, creating persistent supply-side or classical unemployment. Their solution is to increase labor-market flexibility, e.g., by cutting wages, busting unions, and deregulating business.

Deficit spending is not Keynesianism. Governments had long used deficits to finance wars. Keynesianism recommends counter-cyclical policies to smooth out fluctuations in the business cycle. For example, raising taxes to cool the economy and to prevent inflation when there is abundant demand-side growth, and engaging in deficit spending on labor-intensive infrastructure projects to stimulate employment and stabilize wages during economic downturns. Classical economics, on the other hand, argues that one should cut taxes when there are budget surpluses, and cut spending—or, less likely, increase taxes—during economic downturns. Keynesian economists believe that adding to profits and incomes during boom cycles through tax cuts, and removing income and profits from the economy through cuts in spending and/or increased taxes during downturns, tends to exacerbate the negative effects of the business cycle.

"Multiplier effect" and interest rates

Two aspects of Keynes's model had implications for policy:

First, there is the "Keynesian multiplier", first developed by Richard F. Kahn in 1931. Exogenous increases in spending, such as an increase in government outlays, increases total spending by a multiple of that increase. A government could stimulate a great deal of new production with a modest outlay if:

1. The people who receive this money then spend most on consumption goods and save the rest.
2. This extra spending allows businesses to hire more people and pay them, which in turn allows a further increase consumer spending.

This process continues. At each step, the increase in spending is smaller than in the previous step, so that the multiplier process tapers off and allows the attainment of an equilibrium. This story is modified and moderated if we move beyond a "closed economy" and bring in the role of taxation: the rise in imports and tax payments at each step reduces the amount of induced consumer spending and the size of the multiplier effect.

Second, Keynes re-analyzed the effect of the interest rate on investment. In the classical model, the supply of funds (saving) determined the amount of fixed business investment. That is, since all savings was placed in banks, and all business investors in need of borrowed funds went to banks, the amount of savings determined the amount that was available to invest. To Keynes, the amount of investment was determined independently by long-term profit expectations and, to a lesser extent, the interest rate. The latter opens the possibility of regulating the economy through money supply changes, via monetary policy. Under conditions such as the Great Depression, Keynes argued that this approach would be relatively ineffective compared to fiscal policy. But during more "normal" times, monetary expansion can stimulate the economy, mostly by encouraging construction of new housing.

Keynes and redistribution

Keynesians and redistributionists tend to associate with each other. Keynes, in the twenties, wrote about a hydro-electric project. In his opinion it would have been better if the rewards of the project had gone to the worker-builders rather than to the investors who had financed the project.

Keynesians believe that fiscal policy should be directed towards the lower-income segment of the population, because that segment is more likely to spend the money, contributing to demand, than to save it.

Postwar Keynesianism

After Keynes, Keynesian analysis was combined with neoclassical economics to produce what is generally termed the "neoclassical synthesis" which dominates mainstream macroeconomic thought. Though it was widely held that there was no strong automatic tendency to full employment, many believed that if government policy were used to ensure it, the economy would behave as classical or neoclassical theory predicted.

In the post-WWII years, Keynes's policy ideas were widely accepted. For the first time, governments prepared good quality economic statistics on an ongoing basis and had a theory that told them what to do. In this era of new liberalism and social democracy, most western capitalist countries enjoyed low, stable unemployment and modest inflation.

It was with John Hicks that Keynesian economics produced a clear model which policy-makers could use to attempt to understand and control economic activity. This model, the IS-LM model is nearly as influential as Keynes' original analysis in determining actual policy and economics education. It relates aggregate demand and employment to three exogenous quantities, i.e., the amount of money in circulation, the government budget, and the state of business expectations. This model was very popular with economists after World War II because it could be understood in terms of general equilibrium theory. This encouraged a much more static vision of macroeconomics than that described above.

The second main part of a Keynesian policy-maker's theoretical apparatus was the Phillips curve. This curve, which was more of an empirical observation than a theory, indicated that increased employment, and decreased unemployment, implied increased inflation. Keynes had only predicted that falling unemployment would cause a higher price, not a higher inflation rate. Thus, the economist could use the IS-LM model to predict, for example, that an increase in the money supply would raise output and employment—and then use the Phillips curve to predict an increase in inflation.

Through the 1950s, moderate degrees of government demand leading industrial development, and use of fiscal and monetary counter-cyclical policies continued, and reached a peak in the "go go" 1960s, where it seemed to many Keynesians that prosperity was now permanent. However, with the oil shock of 1973, and the economic problems of the 1970s, modern liberal economics began to fall out of favor. During this time, many economies experienced high and rising unemployment, coupled with high and rising inflation, contradicting the Phillips curve's prediction. This stagflation meant that the simultaneous application of expansionary (anti-recession) and contractionary (anti-inflation) policies appeared to be necessary, a clear impossibility. This dilemma led to the end of the Keynesian near-consensus of the 1960s, and the rise throughout the 1970s of ideas based upon more classical analysis, including monetarism, supply-side economics[citation needed] and new classical economics. At the same time Keynesians began during the period to reorganize their thinking (some becoming associated with New Keynesian economics); one strategy, utilized also as a critique of the notably high unemployment and potentially disappointing GNP growth rates associated with the latter two theories by the mid-1980s, was to emphasize low unemployment and maximal economic growth at the cost of somewhat higher inflation (its consequences kept in check by indexing and other methods, and its overall rate kept lower and steadier by such potential policies as Martin Weitzman's share economy

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