Prediction intervals for heteroscedastic series by holt-winters methods

Abstract

The paper illustrates a procedure to calculate prediction intervals in case of heteroscedasticity using Holt-Winters methods. The procedure has been applied to the Italian daily electricity prices (PUN) of the year 2014; then the prediction intervals have compared to those provided by an ARIMA-GARCH model. The intervals obtained with HW methods have been very similar to the others, but easier to calculate. Moreover, the HW procedure is more flexible in dealing with periodic volatility as proved in the case study.