I’ve had a few questions on this topic lately. Here is an email received today: I use Eviews to estimate time series, but I have been checking out R recently, and your Forecast package. I cannot understand why 2 similar equations in Eviews and R are giving different estimated output. Your insights will be invaluable for my work. The equations are: R: Arima(log(fee), order=c(1,1,0), seasonal=list(order=c(1,0,0), period=4), include.drift=TRUE) Eviews: dlog(fee) c ar(1) sar(1) Even with …