are you using a iterative method, if that is the case, try different
starting values.
--
Charles Koss
http://charlesonnet.blogspot.com/
On Mon, Dec 21, 2009 at 6:24 PM, Ekrem Kalkan <[email protected]> wrote:
> I see your point, but in my case every equation has 860 number of
> observartion. Still, I think there should be a different reason rather
> than degrees of freedom. Thank you very much anyway.
>
>
> 2009/12/22 Maarten buis <[email protected]>:
>> --- On Mon, 21/12/09, Ekrem Kalkan wrote:
>>> I am estimating a system of 14 equations, each with
>>> nearly 40 variables. I have also 20 excluded instruments. What
>>> do you mean by "empty"model? If you mean the model without
>>> explanatory variables, there will be only 14 constant term to
>>> be estimated. Is it too large?
>>
>> I am afraid that this could very well be the case. Think of it
>> this way: you have only a bit more than 60 observations per
>> equation. 60 is OK but not great for linear regression, as it
>> is known to be robust, well behaved, and stable, but your are
>> realy pushing your luck when using such small sample sizes for
>> anything more complicated. This is especially true for anything
>> involving instrumental variables, these models can easily eat
>> huge amounts of statistical power.
>>
>> I hope I haven't ruined your Christmas,
>> Maarten
>>
>> --------------------------
>> Maarten L. Buis
>> Institut fuer Soziologie
>> Universitaet Tuebingen
>> Wilhelmstrasse 36
>> 72074 Tuebingen
>> Germany
>>
>> http://www.maartenbuis.nl
>> --------------------------
>>
>>
>>
>>
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>
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