Essays on Purchasing Power Parity, Real Exchange Rate, and Optimum Currency Areas

Abstract: This thesis contains three separate papers. Paper I tests whether the theory of Purchasing Power Parity holds in a selected sample of twenty African countries. The paper employs a panel unit root test to test whether the real exchange rates in the panel are mean reverting or not. The test employed is the Im et al (1997) test. Results show that the null of a unit root is rejected for the three real exchange rate indices, namely, the import-based and trade-weighted multilateral indices, and the bilateral indices, while for the export-based indices, the null hypothesis is not rejected. That is, Purchasing Power Parity is confirmed for the import-based and trade-weighted multilateral indices, and the bilateral indices, while it is rejected for the export-based multilateral indices. After performing the demeaning adjustment to account for cross-sectional dependence, our results show that the null hypothesis of a unit root is rejected for the import-based multilateral indices and the bilateral indices, while the null is not rejected for the trade-weighted multilateral indices. Purchasing Power Parity is therefore only confirmed for the import-based multilateral indices and bilateral indices, while it is rejected for the trade-weighted multilateral indices. Paper II analyses the main determinants of the real exchange rate in Zambia. It first gives a brief review of the Zambian economy and a review on real exchange rate studies. Then an illustrative model is presented. The study employs cointegration analysis in estimating the long-run determinants of the real exchange rates for imports and exports, and of the internal real exchange rate. The finding is that terms of trade, government consumption, and investment share all influence the real exchange rate for imports, while terms of trade, central bank reserves and trade taxes influence the real exchange rate for exports in the long-run. The internal real exchange rate is influenced by terms of trade, investment share, and the rate of growth of real GDP in the long-run. Error-correction models are then estimated. iii Besides the difference of the fundamentals mentioned above, aid and openness are found to impart short-run effects on the real exchange rate indices. The coefficients of adjustment are found to be -0.38, -0.79 and -0.80 respectively for the real exchange rates for imports and exports, and for the internal real exchange rate. Paper III investigates whether the East African Community, comprising of Kenya, Tanzania, and Uganda, constitutes an optimum currency area or not. The East African Community has been revived, and one of the long-term objectives of the Community is to have a common currency. The paper employs the Generalised Purchasing Power Parity method, and various criteria suggested by the theory of Optimum Currency Areas to investigate the optimality of the Community as a currency area. While the various indices that we calculated based on the theory of Optimum Currency Areas gave mixed verdicts, the Generalised Purchasing Power Parity method supports the formation of a currency union in the region. Using the Generalised Purchasing Power Parity method, we were able to establish cointegration between the real exchange rates in East Africa for the period 1981 to 1998, and even for the period 1990 to 1998. This finding suggests that the three countries tend to be affected by similar shocks.