Conditional Variance Calculation

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sirooskhadem
Posts: 22
Joined: Tue Nov 19, 2013 12:23 am

Conditional Variance Calculation

Postby sirooskhadem » Wed Jan 15, 2014 1:21 am

Hi,

I have been trying to include conditional variance into my model. I have extracted the conditional variance (garch) from the return equation but I would like to know how eviews calculates it.
I have tried this formula [Var = (1/N)*(Return-(@mean(return)))^2]. graphically they are very close but the values are different. I would like to know how eviews calculates the conditional variance then base on that I would be able to also estimate the Conditional skewness and kurtosis.

I would be grateful if anyone can advise me.

Regards,
Siroos

EViews Glenn
EViews Developer
Posts: 2682
Joined: Wed Oct 15, 2008 9:17 am

Re: Conditional Variance Calculation

Postby EViews Glenn » Wed Jan 15, 2014 8:13 am

I'm a little confused by the question. As one might expect, since you estimated a GARCH model, EViews uses your GARCH specification, not the unconditional variance, to compute the conditional variance. It is not surprising that the two differ.

sirooskhadem
Posts: 22
Joined: Tue Nov 19, 2013 12:23 am

Re: Conditional Variance Calculation

Postby sirooskhadem » Wed Jan 15, 2014 9:45 pm

Thank you very much, now it makes scense.

Now my questions is if the formula that I have applied for conditional variance is correct?
Var = (1/N)*(Return-(@mean(return)))^2

What if I remove the scaling by 1/N since I have more than 700,000 observations. Will it be better?

and finally how about the skewness and kurtosis, do they make scense? and if they are correct should I keep the (1/N) or not?

Skew = (1/N)*((Return-(@mean(return)))/(@stdev(return)))^3
Kurt = (1/N)*((Return-(@mean(return)))/(@stdev(return)))^4

Many thanks,
Siroos


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