0. Class Slides for EC 204
To Accompany Chapter 19

1. Learning objectives
This chapter presents an overview of recent work in two areas:
Real Business Cycle theory
New Keynesian economics

2. The 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

3. The 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.
The real question here is: what 5 compact discs did Robinson bring to the island?
Doesn’t it seem silly to ponder the “desert island disc” question? I mean, if you knew you were going to be stranded on a desert island, you’d avoid the trip altogether rather than bringing your five favorite discs. And do desert islands even have cd players? I saw “Cast Away” with Tom Hanks twice and didn’t see a cd player either time.

4. Shocks 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.
This slide presents two examples of shocks, and the responses of economic variables to each shock. The textbook also describes a third shock, an attack by the natives that spurs an increase in “defense spending” and a “wartime boom” in the economy.

5. Economic fluctuations as optimal 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 desirable. But once they occur, fluctuations in output, employment, and other variables are the optimal responses to them.

6. The 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?

7. The 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:
(1+r)W1 / W2
where W1 is the wage in period 1 (the present) and W2 is the wage in period 2 (the future).

8. The 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

9. Technology 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?

10. The Solow residual and growth in output
Percent per year 10 8
Output growth 6 4 2
Figure 19-1 on p.506.
Students should note that the Solow residual is strongly correlated with output growth. -2
Solow residual -4
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
Year

11. Technology 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.
Why is the Solow residual biased?
In a recession, firms cut back on their output. But because of the costs of firing workers (such as lower morale among the remaining workers) and the costs of hiring workers back when the recession ends, firms “hoard labor” rather than let go of it. They give unneeded workers tasks such as organizing the file cabinets, or let workers take more coffee breaks. In booms, firms don’t hire as many new workers as theory might suggest, instead making their existing workers work harder. As a result, observed employment appears less cyclical than firms’ true use of labor in production, and the Solow residual then appears to move more closely with output.

12. Productivity 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.

13. The 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.

14. The 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.

15. New 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.

16. Small menu costs and aggregate-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.

17. 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.

18. Recessions 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.
The textbook (p.511) shows a game between two firms in which both would be better off if both cut prices, but each is unwilling to cut price first; in the equilibrium, neither cuts its price.

20. The 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.
The text does not discuss contracts, but contracts may also explain price stickiness:
The cost of negotiating may be sufficiently high that buyers and sellers agree to a contract that fixes the price for the duration of the contract’s life. However, we are trying to explain the stickiness of nominal prices. One wonders why contracts do not specify a real price (i.e., index the nominal price to a measure of the price level), as the elimination of inflation uncertainty would make buyer and seller better off (provided both are risk averse).

22. Top reasons for sticky prices: results from surveys of managers
1. 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
See Table 19-2 on p.515 for more information.
This slide lists theories of price stickiness in the order in which they were most frequently cited by managers. The survey considered 12 theories; this slide lists the top 6, all of which were accepted by 30% or more of the managers that responded to the survey.

24. Inflation 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.

25. Inflation 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

26. Inflation 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.

27. Inflation 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

28. Conclusion: 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.

29. Chapter summary assumes perfect flexibility of wages and prices
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

30. Chapter 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