Australia’s Real Exchange Rate – Is it Explained by the Terms of Trade or by Real Interest Differentials?

We use time series techniques to examine the behaviour of Australia’s real exchange rate from 1969 to 1990. The real exchange rate exhibits non-stationary behaviour over this period, in contrast to simple purchasing power parity theory. We find weak evidence that the real exchange rate exhibits a stable long run relationship with the terms of trade. There is no stable long run relationship between the real exchange rate and either short or long real interest differentials between Australia and its major trading partners. Since the float of the Australian dollar and the world-wide deregulation of financial markets, we find some evidence that the real exchange rate exhibits a stable relationship with the terms of trade alone, and with long real interest differentials alone. The evidence for a stable relationship is clearest with long real interest differentials. After the float, we also find evidence that the terms of trade and long real interest differentials together help to explain the Australian real exchange rate. We estimate the number of independent long run relationships between the real exchange rate, the terms of trade and long real interest differentials and, for some specifications, find evidence of two independent relationships. Since the float, our best estimates are that a 1 per cent improvement in the terms of trade leads to an appreciation of the Australian real exchange rate of about 0.3 to 0.5 per cent, while an increase of 1 percentage point in the differential between Australian and world long real interest rates is associated with an appreciation of the Australian real exchange rate of about 2 to 3½ per cent.