Exchange Rate Regimes and Monetary Policy Dynamics

Exam Tip: If a question asks why fixed exchange rates seem "bad" in the short run, focus on the loss of monetary autonomy. The central bank cannot use interest rates to combat domestic recessions because it must prioritize the exchange rate peg.

The Medium Run: The Return to Equilibrium

While the short-run outcomes differ significantly, the medium-run perspective offers a different view. In the medium run, the economy tends to return to its potential output level.

A crucial concept here is real depreciation. The real exchange rate ($\epsilon$) is defined as: $\epsilon = \frac{E \cdot P^*}{P}$ where $E$ is the nominal exchange rate, $P^\*$ is the foreign price level, and $P$ is the domestic price level.

There are two ways to achieve real depreciation:

1. Nominal Depreciation: A decrease in the nominal exchange rate ($E \downarrow$).
2. Price Level Adjustment: A decrease in the domestic price level relative to the foreign price level ($P/P^* \downarrow$).

In the short run, only the first option is available under flexible rates. However, in the medium run, the second option becomes available under any regime. For instance, under a fixed exchange rate, if output is below potential ($Y < Y^n$), the Phillips curve implies that inflation will be lower than expected ($\pi < \bar{\pi}$). This lower domestic inflation relative to foreign inflation leads to a real depreciation, which eventually pushes output back up to its potential level.

Exchange Rate Crises

Both regimes are susceptible to exchange rate crises, but the mechanics differ.

Fixed Exchange Rate Crises

A crisis often arises from a "self-fulfilling prophecy". If investors believe a country will eventually be forced to devalue its currency (perhaps due to a large trade deficit or low output), they will attempt to move their capital out of the country. To maintain the peg, the central bank must raise interest rates to prevent capital flight. However, if the expected devaluation is large, the required interest rate might be prohibitively high (e.g., needing to be 60% above foreign rates to offset a 5% monthly devaluation risk). This often leads to a deep recession, eventually forcing the government to give in and devalue.

Flexible Exchange Rate Volatility

In flexible regimes, the exchange rate is driven by expectations of future interest rates and future exchange rates. A sudden change in the current account or a shift in investor sentiment regarding future interest rates can cause immediate and significant volatility in the current exchange rate.

Choosing a Regime and Modern Monetary Policy

Economists generally favor flexible exchange rates because they allow for automatic adjustments to shocks, despite the downside of volatility. Fixed rates are typically reserved for two exceptions:

1. Low Credibility: When a central bank cannot be trusted, a "hard peg" (like dollarization or a currency board) can provide stability.
2. Integration: When countries are highly integrated, a common currency may be optimal.

Conventional vs. Unconventional Policy

Modern monetary policy has evolved through two main stages:

1. Conventional Monetary Policy: Most central banks now practice inflation targeting, committing to a medium-run inflation target. They often follow the Taylor Rule, which prescribes how to adjust the nominal interest rate ($i_t$) based on inflation deviations ($\pi_t - \pi^*$) and unemployment deviations ($u_t - u_n$): $i_t = i^* + a(\pi_t - \pi^*) - b(u_t - u_n)$ where $a > 1$.

2. Unconventional Monetary Policy: When interest rates hit the Zero Lower Bound (ZLB), conventional tools become ineffective. Central banks then turn to:

• Quantitative Easing (QE): Buying long-term government bonds to increase the money supply and lower long-term interest rates by reducing the risk premium.
• Forward Guidance: Directly influencing market expectations regarding future short-term interest rates.

Summary Table: Policy Comparison

In conclusion, while the choice of exchange rate regime dictates the immediate flexibility of a nation's economy, the medium-run equilibrium remains driven by fundamental adjustments in prices and output. Understanding these dynamics is vital for navigating the complexities of global finance and central bank interventions.