4Lecture: aggregate demand and aggregate supply
Aggregate Demand
Definition: Aggregate Demand (AD) represents the total quantity of goods and services demanded across all levels of an economy at a given overall price level and in a given time period.
Components of Aggregate Demand:
personal Consumption (C): The total spending by households on goods and services.
consumer confidence
tax policy - personal taxes
gov’t stimulus
Investment (I): The spending on capital goods that will be used for future production.
business expectatoins
interest rate policy(central bank)
tax policy - corporate and capital gains taxes
Government Spending (G): The total government expenditures on goods and services. It includes spending on public services and infrastructure.
defense
infrastructure
Net Exports (NX): The total value of a country’s exports minus its imports. Positive net exports contribute to aggregate demand.
foreign income
exchange rates
foreign price level
trade policies
Formula: where:
$C$ = Consumption
$I$ = Investment
$G$ = Government Spending
$X$ = Exports
$M$ = Imports
Multiplier
means that changes in one component will cause the curve to shift y more than the inital shift
marginal propensity to consume: the portion of extra income that households spend rather than save, calculated as the Change in Consumption divided by the Change in Income (MPC = ΔC/ΔY)
equivalence and leakages(savings, taxes, imports) are funds leaving the circular flow of income
Shifts in Aggregate Demand:
Factors that can shift the AD curve include changes in:
Consumer confidence
Interest rates
Tax policies
Currency exchange rates
Increase in AD: Causes a rightward shift in the AD curve, leading to higher prices and output levels.
Decrease in AD: Causes a leftward shift in the AD curve, leading to lower prices and output levels.
Aggregate Supply
Definition: Aggregate Supply (AS) is the total quantity of goods and services that producers in an economy are willing and able to supply at a given overall price level in a given time period.
Potential output: the maximum level of goods and services an economy can produce when all resources, such as labor and capital, are fully and efficiently employed without causing inflation.
Short-Run Aggregate Supply (SRAS):
In the short run, AS can be influenced by changes in resource prices, taxes, and subsidies, as well as temporary shocks to the economy (e.g., natural disasters).
Factors that shift SRAS(aka Supply Shocks): Productivity(tech, factors of production), capital, and natural resources
Shape: Upward sloping, as higher prices can incentivize firms to increase supply.
Long-Run Aggregate Supply (LRAS):
In the long run, AS is determined by the availability of resources, technology, and institutions.
technology, factors of production, productivity can shift LRAS
Shape: Vertical at potential output, indicating the economy's full capacity output level.
Equilibrium of Aggregate Demand and Supply
Equilibrium: Occurs where the aggregate demand curve intersects the aggregate supply curve.
Impact of Equilibrium Changes:
If AD increases, the price level and output level both increase, leading to inflation in the economy.
If AS decreases due to factors like supply shocks, the economy can experience stagflation, characterized by increased prices and decreased output.
Importance of Understanding AD and AS:
Crucial for policymakers to implement measures to stabilize the economy. Analysis of AD and AS can inform decisions such as adjusting interest rates, taxation, and government spending policies.
Public policy:
faced with a gap
nonintervention policy: the government minimizes its interference in the free market, letting self-correcting forces work, often associated with laissez-faire,
stabilization policy: government actions using fiscal (spending/taxing) and monetary (interest rates/money supply) tools to smooth out business cycle fluctuations, aiming to control inflation, reduce unemployment, and promote steady economic growth (GDP) by managing aggregate demand
expansionary policy: a set of actions by a government or central bank to stimulate economic growth by increasing aggregate demand, typically during a recession or slowdown.
contractionary policy: an economic strategy used by governments or central banks to cool down an overheating economy and combat inflation by decreasing the money supply and slowing economic growth.
tools:
fiscal policy: a government's use of tax and spending policies to influence the economy, typically to stabilize it during business cycles
monetary policy: refers to actions taken by a central bank, like the Federal Reserve, to manage the money supply and credit conditions to achieve macroeconomic goals such as price stability, maximum employment, and stable economic growth.
automatic stabilizers: built-in government budget programs that automatically adjust tax revenues and spending to stabilize the economy during business cycle fluctuations
unemployment compensation
corporate profit tax
progressive income tax
Economic Implications
Inflation: Understanding the relationship between aggregate demand and aggregate supply is essential to managing inflationary pressures in the economy. Higher AD can lead to rising price levels unless matched by an increase in AS.
Unemployment: Shifts in AS and AD can also affect unemployment levels. An increase in AD can lower unemployment by creating more jobs as firms increase production. Conversely, a decrease in AD can result in higher unemployment.
Policy Responses: Governments and central banks may use fiscal and monetary policies to influence AD and AS. For example:
Fiscal Policy: Adjusting government spending and tax policies to stimulate or slow down economic activity.
Monetary Policy: Controlling money supply and interest rates to influence borrowing, spending, and investment.
Conclusion
Aggregate Demand and Aggregate Supply are fundamental concepts in economics, providing insight into overall economic performance, inflation, and employment. A thorough understanding of these concepts helps in the analysis and formulation of economic policies.