The behaviour and fundamental determinants of the real exchange rate in South Africa

Abstract

Real exchange rates have important effects on production, employment and trade, so it is crucial to understand the factors responsible for their variations. This study analyses the main determinants of the real exchange rate and the dynamic adjustment of the real exchange rate following shocks to those determinants, using quarterly South African data covering the period 1975 to 2005. It begins with a review of literature on the determinants of the real exchange rate and provides an updated background on the exchange rate system in South Africa. An empirical model linking the real exchange rate to its theoretical determinants is then specified. In contrast to previous analyses, this study augments the cointegration and vector autoregression (VAR) analysis with impulse response and variance decomposition analyses to provide robust long run effects and short run dynamic effects on the real exchange rate. The variables that have been found to have a long run relationship with the real exchange rate include the terms of trade, real interest rate differential, domestic credit, openness and technological progress. The estimate of the speed of adjustment coefficient found in this study indicates that about a third of the variation in the real exchange rate from its equilibrium level is corrected within a quarter. The impulse response functions broadly corroborate the theoretical predictions, but only the terms of trade, domestic credit and openness have a significant impact on the real exchange rate in the short run. However, only shocks to the terms of trade and domestic credit have persistent effects on the real exchange rate. Results from the variance decompositions are largely similar to those from the impulse response analysis. The terms of trade, domestic credit and openness are the only variables found to significantly explain the variation in the real exchange rate. The most interesting result that emerged from this analysis and is supported by previous research is that among other determinants, the terms of trade explain the largest proportion of the variation in the real exchange. On balance, the evidence therefore suggests that real exchange rate fluctuations are predominantly equilibrium responses to real and monetary shocks rather than fiscal policy shocks.