The Arima() function in the R forecast package contains an "include.drift" parameter. Could someone explain how this is calculated and how it is included in point forecasts?
According to this post by Rob Hyndman this parameter is usally used when the series is differenced at least once. Nevertheless when I include it in forecasts for a undifferenced series it seems to produce more realistic forecasts. I would like to know why that is. Thanks in advance for any help.