Unit Overview
National Income and Price Determination Overview
AP MacroeconomicsΒ· 5 min read π 10-15% of total AP exam score
1. Unit at a Glance
This unit builds on your understanding of business cycles from Unit 2 to construct a complete model of how the overall economy works. We build the model incrementally: starting with its core components (aggregate demand, short-run aggregate supply, long-run aggregate supply) before exploring how shifts in these curves change equilibrium outcomes.
Next we cover how the economy self-adjusts to shocks over the long run, then turn to how government fiscal policy can be used to speed up recovery from business cycles, ending with key concepts that shape policy effectiveness: the multiplier effect and crowding out.
Below are all sub-topics in this unit, ordered to build your understanding step-by-step:
AP Macroeconomics Aggregate Demand
Learn the definition of aggregate demand and the reasons its curve is downward-sloping.
β β β± 7 min
AP Macroeconomics Automatic Stabilizers
Understand how built-in government policies stabilize output without new discretionary action.
β β β± 5 min
AP Macroeconomics Equilibrium in the AD-AS Model
Calculate and interpret short-run and long-run equilibrium output and price levels.
β β β β± 8 min
AP Macroeconomics Fiscal Policy
Analyze how expansionary and contractionary fiscal policy shift aggregate demand to close output gaps.
β β β β± 7 min
AP Macroeconomics Long-Run Adjustment to Macroeconomic Shocks
Explore how the economy self-corrects from output gaps through wage and price adjustments.
β β β β β± 8 min
AP Macroeconomics Long-Run Aggregate Supply
Understand why LRAS is vertical and its relationship to an economy's potential output.
β β β β± 6 min
AP Macroeconomics Short-Run Aggregate Supply
Explain why SRAS is upward-sloping and what factors cause it to shift.
β β β β± 7 min
AP Macroeconomics Short-Run Changes to the AD-AS Model
Analyze the short-run impact of common aggregate demand and aggregate supply shocks.
β β β β β± 8 min
AP Macroeconomics The Multiplier Effect and Crowding Out
Calculate the multiplier effect and explain how crowding out reduces fiscal policy impact.
β β β β β± 9 min
2. Common Pitfalls
Wrong move:
Confusing the shapes and roles of SRAS and LRAS
Why:
Misidentifying which curve shifts for a given shock leads to entirely incorrect analysis of outcomes
Correct move:
Remember SRAS reflects sticky prices/wages in the short run, while LRAS is vertical at potential output determined by real resources
Wrong move:
Assuming all fiscal impact is from discretionary policy
Why:
Automatic stabilizers reduce output gap size automatically, changing the required scale of new policy
Correct move:
Always account for automatic stabilizers when evaluating total fiscal impact on aggregate demand
Wrong move:
Treating the multiplier and crowding out as mutually exclusive
Why:
Both effects occur simultaneously, so the net impact depends on their relative size
Correct move:
The net change in AD from fiscal policy is the balance of the multiplier's expansion and crowding out's contraction
3. Quick Reference Cheatsheet
Key Concept | Rule / Formula |
|---|---|
Downward-sloping AD | Slope explained by wealth effect, interest-rate effect, exchange-rate effect |
Spending Multiplier | |
LRAS Curve | Vertical at potential output (), determined by available resources and technology |
Recessionary Gap | Equilibrium output < , results in cyclical unemployment |
Inflationary Gap | Equilibrium output > , creates upward pressure on the price level |
Expansionary Fiscal Policy | Increase government spending / cut taxes β shifts AD right β closes recessionary gap |
Contractionary Fiscal Policy | Decrease government spending / raise taxes β shifts AD left β closes inflationary gap |
Automatic Stabilizers | Progressive taxes and transfer payments that reduce AD volatility without new legislation |
What's Next
Begin this unit by learning the first core component of the AD-AS model: aggregate demand. Once you complete all sub-topics in this unit, you will move on to Unit 4: Financial Sector, where you will build on this framework to analyze how monetary policy impacts macroeconomic outcomes.