On the Sources of Uncertainty in Exchange Rate Predictability∗

We analyse the role of time-variation in coeffi cients and other sources of uncertainty in exchange rate forecasting regressions. Our techniques incorporate the notion that the relevant set of predictors and their corresponding weights, change over time. We find that predictive models which allow for sudden, rather than smooth, changes in coeffi cients significantly beat the random walk benchmark in out-of-sample forecasting exercise. Using an innovative variance decomposition scheme, we identify uncertainty in coeffi cients’estimation and uncertainty about the precise degree of coeffi cients’variability, as the main factors hindering models’forecasting performance. The uncertainty regarding the choice of the predictor is small.