Before revision:  A Model Confidence Set approach finds how the forecasting power of the proxy improves significantly after the policy announcement; a multi-step ahead forecasting exercise estimates the duration of the effect, and, by shocking the policy variable, we are able to quantify the reduction in volatility which is more marked for debt-troubled countries.
After revision:  A Model Confidence Set approach finds how the forecasting power of the proxy after the Expanded Asset Purchase Programme implementation; a multi--step ahead forecasting exercise estimates the duration of the effect, and, by shocking the policy variable, we are able to quantify the reduction in volatility which is more marked for debt-troubled countries.