A Doctoral Thesis Submitted in fulfilment of the requirements for the award of Doctor of Philosophy, The Graduate School of Business Administration, University of the Witwatersrand February 2016 / The liberalization of foreign exchange markets occasioned by the widespread acceptance of floating exchange rate systems brought about prevalent acceptance of foreign currency (usually U.S. dollars) in many developing and transition economies. Facing both domestic and foreign imbalances, a number of developing economies have embraced foreign currencies as a store of value (asset substitution), and in some instances as a medium of exchange for domestic transactions (currency substitution). This thesis examines dollarization/currency substitution, its impact on macroeconomic fundamentals, and the challenges it poses for effective formulation and transmission of monetary policy in Ghana. The entire thesis is organised into five empirical essays, each touching on a specific subject within the broad theme of dollarization and economic instability. The first essay explores the macroeconomic determinants of financial dollarization. The evidence establishes that exchange rate depreciation and financial development drive dollarization. Additionally depreciation of the domestic currency increases demand for foreign currencies, while a more developed financial sector tends to curtail dollarization. The second essay models a long-run money demand function for Ghana within the portfolio balance framework. The results indicate that, although foreign interest rates and expected exchange rates (either separately or jointly) are relevant elements in the money demand function, there evidence is more in support of capital mobility and not currency substitution. The third essay provides evidence on how financial dollarization affects the volatility of nominal and real Ghana cedi/U.S. dollar exchange rates. The study showed that the effect of financial dollarization on nominal exchange rate volatility in Ghana is positive, thus, as demand for U.S. dollars becomes more extensive, the cedi/dollar exchange rate becomes more volatile and unstable. The fourth essay investigates the role of dollarization in the dynamics of inflation and inflation uncertainty. Contrary to common logic, the results indicate that dollarization has not played a significant role in the dynamics of inflation volatility. The study posits that, although there is no significant impact of dollarization on inflation volatility, inflation targeting affects the inflation-inflation uncertainty relationship in Ghana. The last essay considers the effectiveness of monetary policy transmission in Ghana and examines whether the degree of dollarization hinders or facilitates that process by accounting for the role of the inflation targeting. The results show that credit and exchange rate channels dominate the transmission mechanism, with the former assuming a more significant role in the inflation targeting period. Moreover, the contribution of dollarization has diminished in the post-inflation targeting era, suggesting that monetary authorities have paid more attention to the effects of dollarization in the current monetary regime. A number of policy prescriptions arising from the thesis are presented to guide domestic authorities in smoothing the path of the instability in the economy. / MB2016

MSc (Statistics) / Department of Statistics / Over the years researchers have been modeling inflation rate in Ghana using linear models such as Autoregressive Integrated Moving Average (ARIMA), Autoregressive Moving Average (ARMA) and Moving Average (MA). Empirical research however, has shown that financial data, such as inflation rate, does not follow linear patterns. This study seeks to model and forecast inflation in Ghana using nonlinear models and to establish the existence of nonlinear patterns in the monthly rates of inflation between the period January 1981 to August 2016 as obtained from Ghana Statistical Service. Nonlinearity tests were conducted using Keenan and Tsay tests, and based on the results, we rejected the null hypothesis of linearity of monthly rates of inflation. The Augmented Dickey-Fuller (ADF) was performed to test for the presence of stationarity. The test rejected the null Hypothesis of unit root at 5% significant level, and hence we can conclude that the rate of inflation was stationary over the period under consideration. The data were transformed by taking the logarithms to follow nornal distribution, which is a desirable characteristic feature in most time series. Monthly rates of inflation were modeled using threshold models and their fitness and forecasting performance were compared with Autoregressive (AR ) models. Two Threshold models: Self-Exciting Threshold Autoregressive (SETAR) and Logistic Smooth Threshold Autoregressive (LSTAR) models, and two linear models: AR(1) and AR(2), were employed and fitted to the data. The Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC) were used to assess each of the fitted models such that the model with the minimum value of AIC and BIC, was judged the best model. Additionally, the fitted models were compared according to their forecasting performance using a criterion called mean absolute percentage error (MAPE). The model with the minimum MAPE emerged as the best forecast model and then the model was used to forecast monthly inflation rates for the year 2017. The rationale for choosing this type of model is contingent on the behaviour of the time-series data. Also with the history of inflation modeling and forecasting, nonlinear models have proven to perform better than linear models. The study found that the SETAR and LSTAR models fit the data best. The simple AR models however, out-performed the nonlinear models in terms of forecasting. Lastly, looking at the upward trend of the out-sample forecasts, it can be predicted that Ghana would experience double digit inflation in 2017. This would have several impacts on many aspects of the economy and could erode the economic gains i made in the year 2016. Our study has important policy implications for the Central Bank of Ghana which can use the data to put in place coherent monetary and fiscal policies that would put the anticipated increase in inflation under control.