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Automatic ARIMA forecasting
Posted: Fri Mar 11, 2016 5:13 am
by ESVAL2016
Good evening, for all
I want to use "Automatic ARIMA forecasting" in EViews9, and I am dealing with two-time series, one of them is non-stationary its represent the endogenous variable(Y), and another one its stationary series and its represent the exogenous variable(X), OK.
My problem is:
When I applied "Automatic ARIMA forecasting", to perform this model, I observed the non-stationary series not transformed to be stationary series for example(DY)!!
How to solve this problem in EViews programme?
Best Regards,
Re: Automatic ARIMA forecasting
Posted: Wed Mar 16, 2016 5:31 am
by ESVAL2016
Hello, for all
Why are there a big difference in the result in Automatic ARIMA forecasting AND estimate equation !!? Which method is the right way??
Thanks for your help.
Re: Automatic ARIMA forecasting
Posted: Wed Mar 16, 2016 6:37 am
by EViews Gareth
There should not be big differences.
Re: Automatic ARIMA forecasting
Posted: Wed Mar 16, 2016 4:31 pm
by ESVAL2016
For example,
My model (1,1,0)(1,0,1)12 by estimate equation, I have AIC = 7.347764 AND R^2 =38%
The same model by Automatic ARIMA forecasting, I have AIC= 7.500708 AND R^2=94%
I think its big difference !!
Re: Automatic ARIMA forecasting
Posted: Wed Mar 16, 2016 4:36 pm
by EViews Gareth
Was the same sample used? Automatic forecasting will drop more observations, usually.
Re: Automatic ARIMA forecasting
Posted: Thu Mar 17, 2016 6:19 pm
by ESVAL2016
Yes, I used the same sample in both methods !!
Also, Automatic ARIMA doesn't transform my non-stationary series !!
Therefore,
I think estimate equation box is the best way to find the better model
What is your opinion?
Re: Automatic ARIMA forecasting
Posted: Thu Mar 17, 2016 6:46 pm
by EViews Gareth
I doubt the same sample was used for estimation of the chosen model. Check the output carefully.
Re: Automatic ARIMA forecasting
Posted: Fri Mar 18, 2016 6:02 am
by ESVAL2016
Only, one difference in the work, I take the first difference of my original series. Because the automatic way is not transformed the non-stationary series !!
Re: Automatic ARIMA forecasting
Posted: Fri Mar 18, 2016 8:17 am
by ESVAL2016
What is your opinion?
Which way is the right way to find the best model??
Re: Automatic ARIMA forecasting
Posted: Fri Mar 18, 2016 9:30 am
by EViews Gareth
Not really sure what the issue is.
If you believe the series should be differenced, difference it and then use the automatic arima selection.
If you believe the series should be differenced and follows an exact arima specification, then use that specification and don't use the automatic selection.