Dornbusch Overshooting Model Quiz: Exchange Rate Dynamics

The Dornbusch overshooting model explains why exchange rates are so volatile in the short run. It argues that because goods prices are sticky and adjust slowly, financial markets including the foreign exchange market must adjust immediately to any monetary shock. This causes the exchange rate to move more than its long-run equilibrium requires in the short run, producing overshooting, before gradually returning to the new long-run level as goods prices catch up.

The answer is False. A core assumption of the Dornbusch model is that goods prices are sticky in the short run and adjust slowly over time, whereas financial market prices including exchange rates adjust immediately. This asymmetry in adjustment speeds is the key mechanism that produces overshooting. If prices adjusted instantly like exchange rates, there would be no overshooting because the full long-run adjustment would occur simultaneously across all markets.

Rudiger Dornbusch introduced the overshooting model in a landmark 1976 paper written in response to the adoption of floating exchange rates in 1973 and the subsequent observation that exchange rates were far more volatile than purchasing power parity predicted. Dornbusch showed that this volatility is a rational and predictable consequence of sticky goods prices combined with flexible financial markets, not a sign of market irrationality or inefficiency.

Overshooting means the exchange rate initially reacts to a monetary shock by moving further than its new long-run equilibrium value. For example, after a monetary expansion, the exchange rate depreciates beyond the level that purchasing power parity would predict in the long run. Over time, as goods prices gradually adjust and the real exchange rate corrects, the nominal exchange rate slowly appreciates back toward its new long-run equilibrium level, completing the full adjustment process.

The Dornbusch model relies on three key assumptions: goods prices are sticky in the short run, financial markets clear immediately so exchange rates adjust instantly, and uncovered interest parity holds so expected exchange rate change offsets any interest rate differential. The claim that purchasing power parity holds in the short run is explicitly rejected; Dornbusch showed that PPP holds only in the long run as prices fully adjust, not instantaneously after a monetary shock.

The answer is True. In the long run, the Dornbusch model is fully consistent with purchasing power parity. A permanent increase in the money supply raises the price level proportionally in the long run and the exchange rate depreciates by the same proportion. The model does not dispute long-run neutrality of money. What it adds is the explanation for why the exchange rate overshoots this long-run level in the short run before gradually converging back to it.

Uncovered interest parity is central to the Dornbusch model. It states that the difference between domestic and foreign interest rates equals the expected rate of change of the exchange rate. After a monetary expansion lowers domestic interest rates, uncovered interest parity requires that the currency be expected to appreciate over time to compensate investors. This is only possible if the exchange rate first depreciates far enough beyond its long-run level to create room for the expected future appreciation.

In the long run, the Dornbusch model predicts that goods prices rise in proportion to the money supply increase. As prices adjust upward, the initially expanded real money supply contracts back to its equilibrium level, interest rates return to the world rate, and the real exchange rate returns to its pre-shock value. The nominal exchange rate settles at a new depreciated level consistent with purchasing power parity, completing the full adjustment from short-run overshooting to long-run equilibrium.

The answer is False. The Dornbusch model argues that exchange rate volatility under floating regimes is entirely rational and predictable. Because goods prices adjust slowly while financial markets react immediately, rational forward-looking investors cause the exchange rate to overshoot. The apparent excess volatility is not market inefficiency but an equilibrium response to the structural difference in adjustment speeds between the goods market and the financial market in an open economy.

Following a monetary expansion in the Dornbusch model, the exchange rate overshoots its long-run value, the domestic interest rate falls below the world rate requiring expected appreciation under uncovered interest parity, and goods prices rise only gradually as the exchange rate slowly corrects. The claim that goods prices rise immediately and fully is the flexible price assumption the Dornbusch model explicitly rejects; sticky prices in the goods market are its central defining feature.

Before Dornbusch, purchasing power parity was the dominant exchange rate framework but consistently failed to explain large short-run fluctuations observed after the shift to floating exchange rates in 1973. The Dornbusch model bridged this gap by showing that short-run volatility and long-run purchasing power parity are both consistent with rational behavior once sticky goods prices are incorporated, making it highly influential in international macroeconomics.

The answer is True. After the initial overshooting, the exchange rate converges to its long-run level through gradual adjustment in goods prices rather than through further sharp financial market movements. As goods prices slowly rise following the monetary expansion, the real money supply contracts back to equilibrium, interest rates rise back toward the world rate, and the exchange rate gradually appreciates to its new long-run nominal level consistent with purchasing power parity.

The magnitude of overshooting is directly related to the relative adjustment speeds of financial and goods markets. Because financial markets adjust instantaneously while goods prices are stuck, the entire burden of short-run adjustment falls on the exchange rate. The greater the disparity in adjustment speeds, the more the exchange rate must overshoot to ensure that uncovered interest parity holds and rational investors are willing to hold domestic currency assets at the new lower interest rate.

Real-world implications of the Dornbusch model include that exchange rate volatility under floating regimes is rational, that monetary policy creates large short-run moves exceeding long-run values, and that exchange rates correct gradually rather than jumping directly to equilibrium. The claim that pegged regimes always produce superior stability is not a conclusion of the model; it is a separate policy debate that the Dornbusch framework does not resolve.

The saddle path in the Dornbusch model describes the unique stable trajectory along which the exchange rate and price level jointly converge to the new long-run equilibrium after a monetary shock. Starting from the overshooting point, the economy travels along this path as prices slowly adjust and the exchange rate gradually appreciates. Any deviation from the saddle path would cause the economy to diverge away from equilibrium, making it the only stable adjustment route available.