Output Gaps & the AD-AS Model

Output Gaps

An output gap is present when there is a difference between the actual level of real GDP in an economy and the potential level of real GDP (when all factors of production are fully employed).

Output gaps in the AD-AS model

In the short run, GDP falls and rises in every economy, as the economy dips into recession or expands out of recession.
The AD/AS diagram illustrates recessions when the equilibrium level of real GDP is substantially below potential GDP, and booms when this equilibrium level is temporarily above potential GDP.

The implications of potential output

Potential output represents the productive capacity of the economy, or the full employment level of GDP.
When an economy is producing it's potential output, unemployment equals the natural rate of unemployment ("NRU").
This level of unemployment will fluctuate during the business cycle largely due to cyclical unemployment:
- During a boom, unemployment will be lower than the NRU.
- During a recession, unemployment will be higher than the NRU.

Positive output gap

A positive output gap is defined as: “when the actual level of real GDP is more than the potential underlying level of real GDP”. Potential output is shown by the vertical LRAS curve.
This graph shows an equilibrium point where real GDP is greater than the potential output shown by the LRAS.
This output gap is also known as an 'inflationary output gap.'

Negative output gap

A negative output gap is defined as: “when the actual level of real GDP is less than the potential underlying level of real GDP”. Potential output is shown by the vertical LRAS curve.
This graph shows an equilibrium point where real GDP is less than the LRAS, and therefore there is 'spare capacity'.
This output gap is also known as a 'recessionary output gap.'

Policy implications

In a recessionary gap, the economy is in equilibrium but with less than full employment.
In an inflationary gap, demand pushes the economy past potential output creating inflationary pressure.
The key policy implication for either situation is that government needs to step in and close the gap, increasing spending during recessions and decreasing spending during booms to return aggregate demand to match potential output.

1Microeconomics

1.1Competitive Markets: Demand & Suply

1.1.1Markets & Demand

1.1.2Diminishing Marginal Returns

1.1.3Supply

1.1.4Market Equilibrium

1.1.5Price Mechanism

1.1.6Consumer & Producer Surplus

1.1.7IB Multiple Choice - Demand

1.1.8IB Multiple Choice - Supply

1.2Elasticity

1.2.1Elasticities of Demand

1.2.2Factors Affecting Price Elasticity of Demand

1.2.3Elasticity of Supply

1.2.4Price Elasticity of Supply

1.2.5IB Multiple Choice - Price Elasticity of Demand

1.2.6IB Multiple Choice - Price Elasticity of Supply

1.2.7IB Multiple Choice - Other Elasticities

1.3Government Intervention

1.3.1Indirect Taxes & Subsidies

1.3.2Application Question - Taxing Prices or Quantities

1.3.3Subsidies & Price Controls

1.3.4Deadweight Loss & Government Intervention

1.3.5Elasticity & Tax Incidence

1.3.6IB Multiple Choice - Government Intervention

1.4Market Failure

1.4.1Types of Market Failure

1.4.2Introduction to Externalities

1.4.3Negative Externalities

1.4.4Policy for Negative Externalities

1.4.5Positive Externalities

1.4.6The Deadweight Welfare Loss of Externalities

1.4.7Case Study - The Externalities of Education

1.4.8Public Goods & the Free-Rider Problem

1.4.9Asymmetric Information

1.4.10End of Topic Test - Market Failure

1.4.11Application Questions - Market Failure

1.5HL: Theory of the Firm & Market Structures

1.5.1Theory of the Firm & Market Structures

2Macroeconomics

2.1The Level of Overall Economic Activity

2.1.1The Circular Flow of Income

2.1.2Defining GDP

2.1.3Limitations of GDP

2.1.4IB Multiple Choice - Economic Indicators

2.1.5Business Cycles

2.1.6Output Gaps

2.2Aggregate Demand & Aggregate Supply

2.2.1The Aggregate Demand Curve

2.2.2Components of Aggregate Demand

2.2.3Shape of the Aggregate Demand Curve

2.2.4Shifts in Aggregate Demand

2.2.5IB Multiple Choice - Aggregate Demand

2.2.6Short & Long-Run Aggregate Supply

2.2.7Alternative Models of LRAS

2.2.8Equilibrium in the AD-AS Model

2.2.9Output Gaps & the AD-AS Model

2.3Macroeconomic Objectives

2.3.1Introduction to Unemployment

2.3.2Limitations of Unemployment

2.3.3Types of Unemployment

2.3.4Causes & Impact of Unemployment

2.3.5Defining Inflation

2.3.6Measuring Inflation

2.3.7Use of Index Numbers

2.3.8The Consumer Price Index

2.3.9Consequences of Inflation

2.3.10Causes of Inflation

2.3.11Inflation & Unemployment Tradeoff

2.3.12The Short-Run Phillips Curve

2.3.13The Long-Run Phillips Curve

2.4Economic Growth, Poverty & Inequality

2.4.1Measuring Economic Growth

2.4.2Determinants of Productivity

2.4.3Economic Growth & Productivity

2.4.4Absolute & Relative Poverty

2.4.5Inequality

2.4.6Inequality 2

2.4.7Lorenz Curve

2.4.8Government Policy on Poverty

2.4.9End of Topic Test - Poverty & Inequality

2.4.10Application - Inequality & Poverty

2.5Fiscal Policy

2.5.1Introduction to Fiscal Policy

2.5.2Fiscal Policy and AD-AS Model

2.5.3Fiscal Policy Lags

2.5.4Automatic Stabilizers

2.5.5IB Multiple Choice - Fiscal Policy

2.6Monetary Policy

2.6.1Objectives of Monetary Policy

2.6.2Monetary Policy Implementation

2.6.3Monetary Policy & AD-AS Model

2.6.4Monetary Policy Lags & Pitfalls

2.7Supply-Side Policies

2.7.1Supply-Side Policies

2.7.2Supply-Side Policies 2

3The Global Economy

3.1International Trade

3.1.1Globalisation

3.1.2Globalisation for LEDCs

3.1.3Globalisation for MEDCs

3.1.4Comparative Advantage & Trade

3.1.5Protectionism

3.1.6Arguments for Protectionism

3.1.7Arguments Against Protectionism

3.1.8End of Topic Test - Globalisation & Trade

3.1.9Case Study - Globalisation & Trade

3.2Exchange Rates

3.2.1Floating Exchange Rates

3.2.2Fixed Exchange Rate

3.2.3Effect of a Stronger & Weaker Dollar

3.3The Balance of Payments

3.3.1Balance of Payments

3.3.2Balance of Payments 2

3.3.3FDI & Reducing a BoP Deficit

3.4Economic Integration

3.4.1Customs Unions & WTO

3.4.2Merged Currency

3.5Terms of Trade

3.5.1Absolute & Comparative Advantage

3.5.2Gains from Trade

3.5.3Terms of Trade

3.5.4IB Multiple Choice - Comparative Advantage & Trade

3.6Economic Development

3.6.1Factors Influencing Growth & Development

3.6.2International Institutions

3.6.3Measures of Development

3.6.4Barriers to Development

3.6.5Case Study - The Bottom Billion

3.6.6End of Topic Test - Emerging & Developing

3.7The Role of Domestic & International Factors

3.7.1Interventionist Strategies

3.7.2Development Strategies

3.7.3Development Promotion Policies

3.7.4End of Topic Test - Growth & Global Development

3.7.5Application Questions -Growth & Global Development

3.8The Role of International Trade

3.8.1International Institutions

3.8.2End of Topic Test - Globalisation & Trade

3.9The Role of Foreign Aid

3.9.1Aid

3.9.2Limitations of Aid

3.9.3Support for Aid

3.9.4Application Questions - Developing Countries

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