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Class Slides for EC 204Class Slides for EC 204

To Accompany Chapter 19

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Learning objectivesLearning objectives

This chapter presents an overview of recent work in two areas:

Real Business Cycle theory New Keynesian economics

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The Theory of Real Business CyclesThe Theory of Real Business Cycles

all prices flexible, even in short run– implies money is neutral, even in short run

– classical dichotomy holds at all times

fluctuations in output, employment, and other variables are the optimal responses to exogenous changes in the economic environment - natural rate is fluctuating

productivity shocks are the primary cause of economic fluctuations

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The economics of Robinson CrusoeThe economics of Robinson Crusoe

Economy consists of a single producer-consumer, like Robinson Crusoe on a desert island.

Assume Crusoe divides his time between– leisure– working

•catching fish (production)•making fishing nets (investment)

Assume Crusoe optimizes given the constraints he faces.

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Shocks in the Crusoe island economyShocks in the Crusoe island economy

Big school of fish swims by island. Then, GDP rises because Crusoe’s fishing productivity is higher Crusoe’s employment rises: he decides to shift some time from leisure to fishing to take advantage of the high productivity

Big storm hits the island. Then, GDP falls: The storm reduces productivity, so Crusoe spends less time fishing for consumption.

More importantly, investment falls, because it’s easy to postpone making nets until storm passes

Employment falls: Since he’s not spending as much time fishing or making nets, Crusoe decides to enjoy more leisure time.

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Economic fluctuations as Economic fluctuations as optimal responses to shocksoptimal responses to shocks

In Real Business Cycle theory, fluctuations in our economy are similar to those in Crusoe’s economy.

The shocks aren’t always The shocks aren’t always desirable. But once they desirable. But once they

occur, fluctuations in output, occur, fluctuations in output, employment, and other variables employment, and other variables

are the optimal are the optimal responses to them.responses to them.

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The debate over RBC theoryThe debate over RBC theory

…boils down to four issues: Do changes in employment reflect voluntary changes in labor supply?

Does the economy experience large, exogenous productivity shocks in the short run?

Is money really neutral in the short run?

Are wages and prices flexible in the short run? Do they adjust quickly to keep supply and demand in balance in all markets?

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The labor marketThe labor market

Intertemporal substitution of labor: In RBC theory, workers are willing to reallocate labor over time in response to changes in the reward to working now versus later.

The intertemporal relative wage equals:

where W1 is the wage in period 1 (the present) and W2 is the wage in period 2 (the future).

(1+r)W1 / W2

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The labor marketThe labor market

In RBC theory, • shocks cause fluctuations in the intertemporal wage

• workers respond by adjusting labor supply

• this causes employment and output to fluctuate

Critics argue that• labor supply is not very sensitive to the intertemporal real wage

• high unemployment observed in recessions is mainly involuntary

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Technology shocksTechnology shocks

In RBC theory, economic fluctuations are caused by productivity shocks.

The Solow residual is a measure of productivity shocks: it shows the change in output that cannot be explained by changes in capital and labor.

RBC theory implies that the Solow residual should be highly correlated with output. Is it?

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Year

Output growth

Solow residual

1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 20001945

10

8

6

4

2

0

-2

-4

Percent per year

The Solow residual and growth in outputThe Solow residual and growth in output

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Technology shocksTechnology shocks

Proponents of RBC theory argue that the strong correlation between output growth and Solow residuals is evidence that productivity shocks are an important source of economic fluctuations.

Critics note that the measured Solow residual is biased, appearing more cyclical than the true, underlying technology.

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Productivity shocksProductivity shocks

Procyclical bias may be due to:– Labor Hoarding - Labor input is overestimated in a recession. Workers are kept on payroll even though they are not working as hard. Just sitting around waiting for recession to end.

– Output Mismeasurement - In a recession, workers may produce things that are hard to measure. They might clean the factory, organize inventory, get some training.

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The neutrality of moneyThe neutrality of money

RBC critics note that reductions in money growth and inflation are almost always associated with periods of high unemployment and low output.

RBC proponents respond by claiming that the money supply is endogenous:– Suppose output is expected to fall.Central bank reduces money supply in response to an expected fall in money demand.

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The flexibility of wages and pricesThe flexibility of wages and prices

RBC theory assumes that wages and prices are completely flexible, so markets always clear.

RBC proponents argue that the extent to which wages or prices may be sticky in the real world is not important for understanding economic fluctuations.

They also prefer to assume flexible prices to be consistent with microeconomic theory.

Critics believe that wage and price stickiness explains involuntary unemployment and the non-neutrality of money.

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New Keynesian EconomicsNew Keynesian Economics

Most economists believe that short-run fluctuations in output and employment represent deviations from the natural rate,and that these deviations occur because wages and prices are sticky.

New Keynesian research attempts to explain the stickiness of wages and prices by examining the microeconomics of price adjustment.

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Small menu costs and Small menu costs and aggregate-demand externalitiesaggregate-demand externalities

There are externalities to price adjustment:A price reduction by one firm causes the overall price level to fall (albeit slightly).This raises real money balances and increases aggregate demand, which benefits other firms.

Menu costs are the costs of changing prices (e.g., costs of printing new menus or mailing new catalogs)

In the presence of menu costs, sticky prices may be optimal for the firms setting them even though they are undesirable for the economy as a whole.

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Small menu costs and sticky prices Small menu costs and sticky prices

At an optimum, firm faces on second-order costs of deviating from optimum.

So, if cost of changing prices is small but a little larger than the cost of not adjusting (i.e., cost of deviating from optimum), then the firm won’t change its price.

This argument requires the firm to have some degree of monopoly power over its price.

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Recessions as coordination failureRecessions as coordination failure

In recessions, output is low, workers are unemployed, and factories sit idle.

If all firms and workers would reduce their prices, then economy would return to full employment.

But, no individual firm or worker would be willing to cut his price without knowing that others will cut their prices. Hence, prices remain high and the recession continues.

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The staggering of wages and pricesThe staggering of wages and prices

All wages and prices do not adjust at the same time.

This staggering of wage & price adjustment causes the overall price level to move slowly in response to demand changes.

Each firm and worker knows that when it reduces its nominal price, its relative price will be low for a time. This makes them reluctant to reduce their price.

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Top reasons for sticky prices: Top reasons for sticky prices: results from surveys of managersresults from surveys of managers1.Coordination failure: firms hold back on

price changes, waiting for others to go first

2.Firms delay raising prices until costs rise

3.Firms prefer to vary other product attributes, such as quality, service, or delivery lags

4.Implicit contracts: firms tacitly agree to stabilize prices, perhaps out of ‘fairness’ to customers

5.Explicit contracts that fix nominal prices

6.Menu costs

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Inflation InertiaInflation Inertia Staggered price setting leads to slow adjustment in the price level in response to changes in aggregate demand.

But, this is not the case for inflation. Inflation is expected to decline when output is above its natural rate and vice versa.

Reason is that the Phillips curve consistent with staggered price setting expresses current inflation as a function of future inflation and the output gap.

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Inflation InertiaInflation Inertia

The evidence contradicts this implication and shows inflation to be highly persistent (e.g., NAIRU theory).

Reasons for this:– Delays in adjusting prices– Indexing fixed prices to inflation between adjustments

– Persistence in deviations of output from its natural rate

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Inflation InertiaInflation Inertia

Perhaps the model is incorrect. Instead of sticky prices, we have sticky information (Mankiw and Reis, QJE 2002)

Firms can freely change prices but may not have latest information available.

So, they set price path when new information is available.

Overlapping information availability leads to backward looking Phillips curve.

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Inflation InertiaInflation Inertia Problems with Sticky Information:– Evidence of fixed prices in the economy

– Most firms do not seem to set predetermined paths for prices

– Fixed prices also appear essential for explaining why shifts in aggregate demand have smaller and short-lasting effects in high inflation economies

– Fixed prices help explain why announcing disinflation policy in advance doesn’t have big effect on ultimate cost

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Conclusion: the frontiers of researchConclusion: the frontiers of research

This chapter has explored two distinct approaches to the study of business cycles: Real Business Cycle theory and New Keynesian Theory.

Not all economists fall entirely into one camp or the other.

An increasing amount of research incorporates insights from both schools of thought to advance our study of economic fluctuations.

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Chapter summaryChapter summary

1. Real Business Cycle theory assumes perfect flexibility of wages and prices

shows how fluctuations arise in response to productivity shocks

the fluctuations are optimal given the shocks

2.Points of controversy in RBC theory intertemporal substitution of labor the importance of technology shocks the neutrality of money the flexibility of prices and wages

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Chapter summaryChapter summary

3.New Keynesian economics accepts the traditional model of aggregate demand and supply

attempts to explain the stickiness of wages and prices with microeconomic analysis, including menu costs coordination failures staggering of wages and prices

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