2013年-世界发展银行全球_Estimating_the_Half-Life_of____________Theoretically_Founded_Real_Exchange_Rate_Misalignments_24页_466kb

Summary of "Estimating the Half-life of Theoretically Founded Real Exchange Rate Misalignments"

Core Content

This paper investigates the short and long-term behavior of real exchange rate (RER) misalignments using a theoretical model that incorporates both intertemporal external equilibrium and internal equilibrium in traded and non-traded markets. The model is based on current account dynamics and Harrod-Balassa-Samuelson (HBS) productivity differentials. The study aims to bridge the gap between theory and empirical analysis by estimating the speed of reversion of RER misalignments to their fundamental-based equilibrium level.

Main Points

• Equilibrium Real Exchange Rate (ERER): The paper defines the equilibrium real exchange rate based on theoretical fundamentals such as terms of trade (TOT), net foreign assets to GDP (NFAy), and HBS productivity differentials.

• Half-life Estimation: The half-life of real exchange rate deviations from equilibrium is estimated at approximately 2.8 years using an unrestricted vector error correction model (VECM). This suggests that 25% of the deviation is corrected within one year.

• Country Variability: The half-life estimates vary across countries. About 34 countries (42.5% of the sample) have a half-life of less than 2.5 years, aligning with non-linear mean reversion models. These estimates are consistent with the predictions of Lothian and Taylor (2000) and Taylor, Peel and Sarno (2001).

• Empirical Methodology: The paper uses an unrestricted VECM approach to model RER misalignments, which allows for the estimation of the speed of mean reversion in a multivariate framework. This method accounts for both short-term adjustments and long-term equilibrium.

• Key Variables:

  • Terms of Trade (TOT): Positive shocks to TOT lead to real appreciation in most countries, except China where they may cause depreciation.
  • Net Foreign Assets (NFAy): Shocks to the NFAy ratio result in significant appreciation or depreciation depending on the country.
  • HBS Productivity Differentials: These are linked to the relative price of non-traded goods, influencing the RER in the long run.

• Exchange Rate Regime Flexibility: The study finds a positive correlation between the half-life of RER deviations and the flexibility of the exchange rate regime. More flexible regimes are associated with longer half-lives.

• Country Case Studies:

  • Argentina: Experiences significant depreciation in response to shocks to the net foreign asset to GDP ratio and productivity differentials. The half-life of deviations is around 2.25 years.
  • China: Shows a faster mean reversion of RER deviations, with a half-life of approximately 1.58 years. Temporary TOT shocks initially depreciate the RER but eventually lead to appreciation.

Key Findings

• The half-life of RER deviations from equilibrium is estimated using an unrestricted VECM, which accounts for the simultaneous adjustment of RER fundamentals.
• The estimated half-life of 2.8 years is close to the lower bound of the consensus interval from Rogoff (1996) and is consistent with non-linear mean reversion models.
• The model reconciles two strands of empirical literature on PPP deviations: linear and non-linear adjustment models.
• The results suggest that the speed of reversion is influenced by the nature of shocks and the structure of the economy, particularly the flexibility of the exchange rate regime and the presence of rigidities or regulations.

Conclusion

The paper contributes to the literature by providing a theoretically grounded approach to estimating the half-life of RER misalignments. It demonstrates that RER deviations adjust toward equilibrium at varying speeds, with the average half-life being 2.8 years. The findings support the use of a multivariate model that captures both short-term dynamics and long-term equilibrium, offering a more accurate assessment of the impact of RER misalignments on economic performance and policy effectiveness.

Methodological Approach

• Unrestricted VECM: Used to estimate the speed of reversion of RER deviations to their fundamental-based equilibrium.
• Cointegration and Error Correction: The model incorporates cointegration and error correction mechanisms to ensure consistency between long-run and short-run behavior.
• Data Sample: The analysis is based on a heterogeneous sample of 80 countries (22 industrial, 58 developing) over the period 1970–2010, with each country having at most 41 observations.

Implications

• Policy Evaluation: The model provides a useful framework for evaluating the impact of macroeconomic policies on RER misalignments.
• Exchange Rate Management: Policymakers can use the half-life estimates to better understand the time required for exchange rate misalignments to correct and to assess the effectiveness of exchange rate interventions.
• Economic Growth: Real undervaluation may lead to growth, but real overvaluation can negatively affect economic performance if it results from weak fundamentals or inconsistent policies.

References

• The paper references several key studies and theories, including:
  • Rogoff (1996): Consensus half-life estimates of PPP deviations.
  • Lothian and Taylor (2000) and Taylor, Peel and Sarno (2001): Non-linear adjustment models.
  • Balassa (1964) and Samuelson (1964): HBS effect and productivity differentials.
  • Obstfeld and Rogoff (1985), Obstfeld and Stockman (1985), and Edwards (1989): Equilibrium conditions in BOP and goods markets.