Transcript short run
Chapter 11 Homework
• Number 1, 4, 8, and 14
Chapter 12
The Role
of Aggregate
Demand in
the Short Run
Emergence of the
Keynesian Short-Run Model
• Classical economists thought that an
economy will self-adjust to any problems.
Economy will always be at or near
full employment.
Called the Long Run Economic Model
• The Great Depression set the stage for a
new short-run economic model.
The Great Depression’s
Challenge to the Long-Run Model
• Most severe economic trauma in U.S. history.
From 1929 to 1933, the unemployment rate
increased from about 3% to almost 25%.
By 1933, real GDP had fallen by almost 27%.
Marriage and birth rates fell.
Participation in radical political movements
increased.
Fear was fostered by not knowing what was
happening or how to fix it.
The Great Depression’s
Challenge to the Long-Run Model (cont’d)
• Following the long-run economic model, the
belief was that the economy would eventually
cure itself.
However, during the1930s it didn’t seem to be
working
• The nation’s short-run suffering required
immediate action.
The Keynesian
Short-Run Model Emerges
• John Maynard Keynes was a professor of
economics at Cambridge University in
England.
The Keynesian
Short-Run Model Emerges (cont’d)
• Keynes’ book, The General
Theory of Employment,
Interest and Money, was
published in 1936.
Arguably the most important
economics book of the 20th
century
It challenged the accepted longrun macroeconomic model.
The Keynesian Challenge to the
Long-Run Model
• The Keynesian model is a short-run model of
the behavior of the macroeconomy that:
Emphasizes the role of aggregate demand and
government action in the macroeconomy
Questions the validity of the long-run model as an
effective guide for macroeconomic policy
The Keynesian Challenge to the
Long-Run Model (cont’d)
• Compared to the Classical long-run model, the
Keynesian model:
Is concerned with the short run
• “In the long run, we’re all dead.”
Focuses on aggregate demand
• Can be shaped by policy
Suggests that the economy could remain below full
employment for prolonged periods
• Because markets don’t adjust quickly
Promotes government stabilization policy
The Keynesian Model and
Economic Policy
• In 1933, President Roosevelt proposed—and
Congress passed—a wide variety of economic
legislation designed to stabilize the economy
and put people back to work.
Roosevelt was unwilling for the economy to “fix
itself”.
Characteristics of the Short-Run Model
• Major belief is that full employment is the
exception rather than the rule.
Advocates an aggressive approach to economic
policy that attacks and cures short-run problems
quickly and effectively.
Characteristics
of the Short-Run Model (cont’d)
• Three pillars of the model
Each is a contradiction of a characteristic of the longrun model.
• Challenges:
Say’s Law
The loanable funds market
Flexible prices and wages
Challenge to Say’s Law
• Say’s Law = “supply creates its own
demand.”
• Keynes taught that demand creates its
own supply.
Aggregate demand motivates firms
• Produce a good only if there is a demand for it.
If something is wrong with the economy, it’s
due to a problem with aggregate demand.
Challenge to the Loanable Funds Market
• Long-run model interest rate adjusted so that the
quantity supplied of funds equals the quantity
demanded of funds.
Saving was channeled into investment spending.
• Short-run model no mechanism converts saving to
investment spending.
• Factors other than the interest rate can also influence
saving and investment:
Disposable income has a major impact on saving.
Expected return on investment affects the decision to invest.
Challenge to Price and Wage Flexibility
• Long-run model freely adjusting prices
and wages.
Based on an economy comprised of small,
competitive firms, workers negotiating their own
wages, and minimal government.
• Short-run model prices and wages are
“sticky downward.”
Based on an economy characterized by:
• Large firms with some control over the prices
they charge
• Workers represented by strong unions with the power to
negotiate wages and other benefits
Price Inflexibility
• Long-run model AD decline leads to
lower prices as the short-run aggregate supply
curve shifts to the right.
Firms are not required to reduce output
or employment.
• Short-run model little pressure for firms to cut
prices.
AD declines firms cut output and employment.
Unless and until prices adjust, the economy will
remain below full employment.
Wage Inflexibility
• long-run model decline AD workers accept
lower nominal wages to keep their jobs.
• short-run model workers resist accepting
lower wages.
Wage stickiness doesn’t allow the economy to selfadjust to a decline in aggregate demand.
• Employers will ultimately have to lay off some workers.