Postby EViews Glenn » Mon Dec 16, 2019 12:06 pm
Funny, I'm not seeing that behavior. Estimation from 1953 to 2018 gives estimates with 789 observations for ARMA-ML. Dynamic forecasting for 2019 gives values starting at -1.04 and ascending gradually to -0.55
As to the behavior that you reported...
I'm not saying that this is what happened, but note that if you estimated the equation for 2019 and then tried to forecast for 2019, you might see the behavior that you observed for the dynamic forecast.
The lagged residuals to initialize the ARMA forecast would be 0 since those were out-of-estimation-sample values with no presample residuals. If the estimation and forecast period are at the beginning of the workfile, EViews will try to adjust the start date of the forecast for you so that you get the required two presample residuals. If in the middle of the workfile, EViews is more respectful of the start of forecast period and does not adjust the start of the requested forecast period for you. In this case, adjusting the forecast period forward by 2 periods yields non-zero forecasts.
However, this may not be the explanation as one would still see zero values for structural forecasts in that period. In fact, unless my brain isn't working properly, I would expect all structural forecasts to be zero for your model whatever the samples.
Note also that while EViews Illustrated has a fine discussion of forecasting, some of the idiosyncracies of presample initialization of residuals and forecast samples are probably beyond the scope of that book.