Key Concepts in Macroeconomics: Multipliers and the IS-LM Model
Fundamental Concepts in Macroeconomic Theory
The Paradox of Thrift
How is the Paradox of Thrift defined?
The Paradox of Thrift states that, in certain economic models, for an economy to increase its overall savings, the government must increase its spending.
Defining Autonomous Variables
What is an autonomous variable?
An autonomous variable is a component that is determined outside the model and is independent of the level of income (Y).
Examples of autonomous variables include:
- Investment (I)
- Public Expenditure (G)
- Exports (X)
- Some components of Consumption (C) and Tax (T)
Exogenous Changes Increasing Equilibrium Income
List all possibilities for changes in exogenous variables that result in increases in equilibrium income.
Increases in equilibrium income can result from:
- Any autonomous increase in spending.
- A reduction in the flat rate tax.
- A reduction in the tax rate.
- An increase in the marginal propensity to consume (MPC).
Understanding Automatic Stabilizers
Why are some mechanisms considered automatic stabilizers?
An automatic stabilizer is a mechanism that automatically reduces the amount of variation in production in response to a variation in autonomous demand. Any factor that narrows down the multiplier effect acts as an automatic stabilizer.
The Full Employment Budget Surplus
What is the full employment budget surplus?
The full employment budget surplus shows the budget surplus calculated at the income level corresponding to full employment or potential output.
The Multiplier Effect and Value Determinants
What is the multiplier and what determines its value?
The multiplier is the measure of the resulting change in income from a change in autonomous spending. It reflects the revenue stream on income and consumption, which are independent.
Its value is modified by:
- A change in the marginal propensity to consume (MPC).
- A change in the tax rate.
Analyzing the Aggregate Demand Function
Explain the aggregate demand function, what it depends on, and how it behaves.
The aggregate demand function (AD) is the ratio (sum) of consumption, investment, and government spending. It represents the total demand at different income levels.
The function has an autonomous part and a part that grows. As income increases, aggregate demand increases, but less than proportionately.
Aggregate Demand depends on:
- The level of income (Y).
- Basic consumption needs.
- The possibilities of government spending.
- Expectations of profitability for investment projects.
Key Definitions in Macroeconomic Modeling
Define the following concepts:
- a) The IS Curve
- The IS curve shows the combinations of interest rate levels and production (output) where planned spending equals income (Y).
- b) The Investment Function
- The investment function shows the planned level of investment expenditure corresponding to each type of interest rate.
- c) The LM Curve
- The LM curve shows the combinations of interest rates and agreed levels of production where the demand for money equals the money supply.
- d) Demand for Money (Real vs. Nominal)
- The nominal demand for money is the amount of currency an individual possesses. On the other hand, the real demand for money is a demand for real balances, representing what individuals can actually buy with the money they hold.