2016年-PIIE彼得森国际经济研究所_Reducing_Government_Debt_Ratios_in_an_Era_of_Low_Growth_11页_226kb

Summary of Policy Brief: Reducing Government Debt Ratios in an Era of Low Growth

Core Content

This Policy Brief by Paolo Mauro and Jan Zilinsky examines the challenges of reducing government debt ratios in advanced economies, particularly in the context of low growth. It highlights the risks of high debt, especially in relation to interest rate increases, and proposes an extended accounting approach to better understand the role of economic growth in shaping debt dynamics.

Main Views

• High Debt Ratios Are Risky: Large government debt-to-GDP ratios pose a significant risk of financial crisis, especially in the event of rising interest rates, which can trigger an interest rate-debt spiral.

• Low Growth Complicates Debt Reduction: The next decade is expected to see lower economic growth due to population aging and lingering crisis effects. This makes it harder to reduce debt through growth alone, as economic expansion is a key factor in lowering debt ratios.

• Fiscal Adjustment Is Imperative: A gradual but sustained fiscal adjustment through expenditure cuts and revenue increases is recommended to reduce the likelihood of debt crisis.

• Interest Rate–Growth Differential Matters: The difference between the interest rate and the growth rate is a critical determinant of the debt-to-GDP ratio. Historically, this differential has played a significant role in both increasing and decreasing debt ratios.

• Investor Perceptions Influence Safety: The concept of a "safe haven" is based on investor perceptions, which can shift abruptly. This makes it risky to assume that high debt ratios are always safe.

Key Information

Debt Ratios and Trends

• Debt-to-GDP Ratios: In advanced economies, the average government debt-to-GDP ratio reached 106% by end-2015, up from 72% in 2007.
• Debt Stability: Despite some fiscal deficit reduction, the debt ratio is expected to remain broadly stable in the coming years.
• Historical Context: Over the past 200 years, declines in long-term growth have been a major driver of rising debt ratios.

Economic Growth and Debt Dynamics

• Extended Accounting Approach: This method accounts for the impact of economic growth on both the debt and expenditure ratios, providing a more accurate picture of how growth affects the debt-to-GDP ratio.
• Primary Surplus and Growth: Economic growth increases tax revenues, which can reduce the fiscal deficit and thereby the debt ratio. However, without policy intervention, the primary surplus is expected to grow in line with GDP.
• Ireland vs. Italy Example: Ireland’s debt ratio fell due to strong economic growth, while Italy’s increased because of weak growth and higher interest rates. This illustrates the importance of growth in debt reduction.

Global Crisis Impact

• Crisis-Driven Debt Increases: The global crisis caused a significant rise in debt ratios, mainly due to low or negative growth and expansionary fiscal policies.
• Policy Measures: These played a major role in increasing debt ratios, especially after the crisis. Before the crisis, larger initial primary surpluses helped offset the impact of weak growth.
• Variation Across Countries: While average debt ratios increased by 31.6 percentage points between 2007 and 2015, individual experiences varied widely. For example, Japan and the U.S. had similar increases, but Italy and Australia had different drivers.

Factors Influencing Debt Ratios

Policy Implications

• Low Interest Rates Offer Limited Relief: While low interest rates reduce immediate debt servicing costs, they do not provide a long-term solution, especially with weak growth.
• Inflation as a Tool Is Unlikely: Inflation is not a viable method for reducing debt ratios in the current context due to central banks' efforts to maintain low inflation targets.
• Extended Accounting Is Crucial: This approach provides a better benchmark for understanding the role of growth in debt dynamics, especially over multiple years.

Conclusion

The brief emphasizes that economic growth is a key factor in determining the trajectory of government debt ratios. With growth expected to be lower in the coming decade, a sustained fiscal adjustment is necessary to mitigate the risk of debt crisis. The extended accounting approach helps quantify the role of growth and policy choices in shaping debt outcomes.