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Scenarios in VEC models

Posted: Tue Jan 25, 2011 8:49 am
by sschaffrath
Hi!

I`m trying to forecast a set of variables using a VEC framework in a model.
I´ve no trouble with the baseline scenario, but when I try to override some of the series it doesn´t really react to it. The results are identical.

Another thing, I´m unable to click in the "use override" button. The only way I get to do it, is if I define an add_factor before (which I don´t really need).

Any ideas?

PS: I´m using Ev6.

Cheers,
Sven.

Re: Scenarios in VEC models

Posted: Tue Jan 25, 2011 8:53 am
by EViews Gareth
Could you post your workfile?

Re: Scenarios in VEC models

Posted: Tue Jan 25, 2011 9:47 am
by sschaffrath
Here it is.

I´m particularly concerned about the overriding of "pbi_mundial" with "pbi_mundial_1" in the exp_arg model.

Re: Scenarios in VEC models

Posted: Tue Jan 25, 2011 10:12 am
by EViews Gareth
You can't apply overrides to the baseline, you have to create a second scenario and apply overrides to that new scenario. Since the model in your workfile doesn't have a second scenario setup, I assume you weren't doing that.

Re: Scenarios in VEC models

Posted: Tue Jan 25, 2011 10:25 am
by sschaffrath
I was doing it, but didn´t save. Sorry for that.

Here it is.

Thanks in advance.

Sven

Re: Scenarios in VEC models

Posted: Tue Jan 25, 2011 10:58 am
by EViews Gareth
pbi_mondail is an endogenous variable in the VEC. You can't override an endogenous variable. You get around this by doing the perfectly sensible thing of marking that variable as an exclude. Unfortunately EViews doesn't support excluding and overriding the same variable. Thus although the variable is being excluded, it is not being overridden.

The easiest thing to do is to break the link on your VEC inside the model (in the equations view, right click on the VEC and select Break Link). Then delete the line corresponding to the variable you want to make exogenous (in this case the last line). Since pbi_mondail now no longer has an equation associated with it, it is strictly an exogenous variable, so you can override it.

Re: Scenarios in VEC models

Posted: Tue Jan 25, 2011 11:12 am
by sschaffrath
My dearest welsh friend, you solved my problem!

Thank you for that! (it was driving me crazy... even more!)

Cheers!
Sven