Cyclically Adjusted Surplus

Cyclically Adjusted Surplus
Cyclically Adjusted Surplus
What is the dictionary definition of Cyclically Adjusted Surplus?
Dictionary Definition of Cyclically Adjusted Surplus

A cyclically adjusted surplus refers to the calculation of a government’s budget surplus or deficit after adjusting for the cyclical fluctuations in the economy. It is a measure used to assess the fiscal health of a government by accounting for the impact of economic cycles on revenue and expenditure. The cyclically adjusted surplus provides a more accurate picture of a government’s fiscal position by removing the temporary effects of economic booms or recessions. This measure is often used to determine the sustainability of a government’s fiscal policy and its ability to meet long-term financial obligations.

Full Definition Of Cyclically Adjusted Surplus

The cyclically adjusted surplus (CAS), also known as the structural surplus or structural budget balance, is a concept used in public finance and economics to evaluate a government’s fiscal position. The CAS accounts for the effects of the economic cycle on government revenues and expenditures, offering a clearer picture of the underlying fiscal health. This legal overview will explore the concept of CAS, its significance, the methodologies used for its calculation, its application in policy-making, and its legal implications within the British context.

Definition and Significance


The Cyclically Adjusted Surplus is the budget balance of a government adjusted for the effects of the economic cycle. It reflects what the surplus would be if the economy were operating at its potential or full employment level. This adjustment is essential because actual budget balances can be misleading during economic booms or recessions. During a boom, higher tax revenues and lower social spending can create a misleading picture of fiscal health, while during a recession, lower tax revenues and higher social spending can exaggerate fiscal weakness.


Understanding the CAS is crucial for several reasons:

  1. Policy Making: It helps policymakers distinguish between cyclical and structural components of the budget. This distinction is vital for making informed fiscal policy decisions.
  2. Fiscal Rules: Many fiscal rules, such as the Stability and Growth Pact in the European Union, are based on cyclically adjusted measures rather than actual budget balances.
  3. Economic Stability: By focusing on the structural budget balance, governments can design policies that promote long-term economic stability, avoiding pro-cyclical fiscal policies that can exacerbate economic fluctuations.

Methodologies for Calculation

Calculating the CAS involves several steps and methodologies. The primary goal is to adjust the actual budget balance to account for the effects of the economic cycle.

Estimating Potential Output

  1. Trend GDP Approach: This method involves estimating the trend or potential GDP using statistical techniques such as the Hodrick-Prescott filter, which separates the cyclical component from the trend component of GDP.
  2. Production Function Approach: This method uses a production function to estimate potential output based on factors such as capital, labour, and technological progress.

Estimating the Output Gap

The output gap is the difference between actual GDP and potential GDP. It indicates whether the economy is operating above or below its potential level.

Adjusting Revenues and Expenditures

Once the output gap is estimated, the next step is to adjust government revenues and expenditures for their cyclical components. This involves estimating elasticities:

  • Revenue Elasticity: The responsiveness of tax revenues to changes in GDP. For instance, income taxes are typically more responsive to GDP changes than indirect taxes like VAT.
  • Expenditure Elasticity: The responsiveness of government expenditures to changes in GDP. (For example, unemployment benefits tend to rise during recessions and fall during booms.)

Application in Policy-Making

The CAS plays a significant role in policy-making, especially in the context of fiscal rules and economic governance.

Fiscal Rules

Many countries have adopted fiscal rules based on cyclically adjusted measures to ensure sustainable public finances. For instance, the Stability and Growth Pact in the European Union requires member states to maintain a structural deficit of no more than 0.5% of GDP. The UK’s Charter for Budget Responsibility includes a target for the cyclically adjusted current budget.

Fiscal Policy

By focusing on the CAS, policymakers can design fiscal policies that are counter-cyclical, helping to stabilise the economy. For example, during a recession, a government may run a cyclically adjusted deficit to stimulate demand, while during a boom, it may aim for a cyclically adjusted surplus to cool down the economy.

Budget Planning

The CAS is also used in budget planning and forecasting. It provides a more accurate picture of the fiscal stance, allowing for better planning and allocation of resources.

Legal Implications

Legal Framework

In the UK, the legal framework for fiscal policy is set out in the Charter for Budget Responsibility. The Charter requires the government to set out its fiscal objectives and targets, including those based on cyclically adjusted measures. The Office for Budget Responsibility (OBR) is responsible for producing independent forecasts and assessments of the government’s fiscal plans, including the CAS.

Compliance and Accountability

The use of the CAS in fiscal rules enhances compliance and accountability. By focusing on the structural budget balance, governments are less likely to engage in short-term fiscal measures that can be politically expedient but economically damaging. The OBR’s role in providing independent assessments ensures transparency and accountability.

Challenges and Criticisms

Despite its advantages, the CAS is not without challenges and criticism.

  • Estimation Errors: Estimating potential output and the output gap is inherently uncertain. Different methodologies can yield different results, leading to debates about the accuracy of the CAS.
  • Elasticity Estimates: The elasticities of revenues and expenditures to GDP can vary over time and across countries, complicating the calculation.
  • Policy Bias: Some critics argue that the focus on structural balances can lead to policy biases, such as underestimating the need for fiscal stimulus during prolonged recessions.

Case Law and Precedents

There is limited case law specifically addressing the CAS, but broader principles of public finance and fiscal responsibility provide relevant precedents.

Judicial Review

In the UK, judicial review of fiscal policy decisions is limited, but courts have occasionally intervened in cases of clear legal breaches. For instance, if the government were to violate its own fiscal rules as set out in the Charter for Budget Responsibility, this could potentially be subject to judicial review, though such cases are rare.

International Precedents

Internationally, the CAS has been used in various contexts, such as in the European Union’s enforcement of the Stability and Growth Pact. The European Court of Justice has ruled on cases involving the interpretation and application of fiscal rules, providing precedents that underscore the importance of cyclically adjusted measures.

Future Developments

The use of the CAS is likely to evolve in response to economic and political developments.

Enhanced Methodologies

Advances in economic modelling and data analysis may improve the accuracy of CAS estimates. For instance, real-time data and machine learning techniques could provide more reliable estimates of potential output and elasticities.

Broader Application

The CAS could be applied more broadly in areas such as environmental fiscal policies. For example, adjusting budget balances for environmental factors could provide a clearer picture of sustainability.

Legal Reforms

There may be legal reforms aimed at strengthening the use of cyclically adjusted measures in fiscal policy. This could include more explicit legal requirements for the CAS in fiscal rules and enhanced roles for independent fiscal institutions like the OBR.


The Cyclically Adjusted Surplus is a vital tool in public finance, providing a clearer picture of a government’s fiscal position by accounting for the economic cycle’s effects. Its significance in policy-making, compliance with fiscal rules, and budget planning underscores its importance. However, the challenges in estimation and potential policy biases must be addressed to enhance its effectiveness. Legal frameworks, such as the UK’s Charter for Budget Responsibility, play a crucial role in ensuring the CAS is used appropriately, promoting transparency and accountability in fiscal policy. As methodologies improve and applications broaden, the CAS will continue to be a cornerstone of sound fiscal management.

Cyclically Adjusted Surplus FAQ'S

Cyclically Adjusted Surplus (CAS) is a measure used in economics to assess the fiscal health of a government. It represents the difference between government revenue and expenditure, adjusted for the cyclical fluctuations in the economy.

CAS is calculated by taking the actual surplus or deficit and adjusting it for the cyclical position of the economy. This adjustment accounts for the impact of economic booms or recessions on government revenue and expenditure.

CAS provides a more accurate picture of a government’s fiscal position by accounting for the cyclical nature of the economy. It helps policymakers understand the underlying strength of the government’s finances and make informed decisions regarding fiscal policy.

The actual surplus or deficit reflects the difference between government revenue and expenditure without considering the impact of economic cycles. CAS, on the other hand, adjusts for these cycles to provide a more stable and reliable measure of fiscal health.

A positive CAS indicates that the government’s revenue exceeds its expenditure, even after accounting for the cyclical fluctuations in the economy. This suggests a strong fiscal position and the ability to save or invest for future needs.

A negative CAS indicates that the government’s expenditure exceeds its revenue, even after adjusting for the cyclical fluctuations in the economy. This suggests a weak fiscal position and the need for corrective measures such as reducing spending or increasing revenue.

While it is possible for governments to manipulate CAS figures for political purposes, the calculation methodology is generally based on objective economic indicators. Independent fiscal institutions or international organisations often monitor and assess the accuracy of CAS calculations to ensure transparency and accountability.

CAS is just one of several fiscal indicators used to assess a government’s financial health. It is often analysed alongside measures such as the actual surplus or deficit, debt-to-GDP ratio, and structural balance to provide a comprehensive view of fiscal sustainability.

CAS calculations rely on economic forecasts and assumptions, which can introduce uncertainties. Additionally, accurately estimating the cyclical position of the economy can be challenging. However, despite these limitations, CAS remains a valuable tool for policymakers to understand the fiscal dynamics of a government.

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This site contains general legal information but does not constitute professional legal advice for your particular situation. Persuing this glossary does not create an attorney-client or legal adviser relationship. If you have specific questions, please consult a qualified attorney licensed in your jurisdiction.

This glossary post was last updated: 6th June 2024.

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