Charles,
I do not understand how the loglikelihood of the restricted model can
be higher than that of unrestricted model. This causes LR-statistic to
be negative (-1311). Do you think these are normal?
Ekrem.
2009/12/21 Charles Koss <[email protected]>:
> Well, you fail to reject the null hypothesis. What is the problem?
>> On Mon, Dec 21, 2009 at 10:23 AM, Ekrem Kalkan <[email protected]> wrote:
>>> Dear Stata users,
>>>
>>> I estimate restricted and unrestricted 3SLS models. I compare these
>>> models with LR test. However, the loglikelihood value of the
>>> restricted model is higher than that of the unrestricted model. To my
>>> knowledge, this is not expected in econometric theory. As the result,
>>> LR-statistics becomes a negative value. Please see my results below.
>>> Can you please comment on this? Thank you.
>>>
>>> . lrtest rSLS3_85 uSLS3_85, stats
>>>
>>> Likelihood-ratio test
>>> LR chi2(65) = -1311.29
>>> (Assumption: rSLS3_85 nested in uSLS3_85) Prob > chi2 = 1.0000
>>>
>>> -----------------------------------------------------------------------------
>>> Model | Obs ll(null) ll(model) df AIC BIC
>>> -------------+---------------------------------------------------------------
>>> rSLS3_85 | 864 . 34853.08 541 -68624.17 -66048.16
>>> uSLS3_85 | 864 . 34197.44 606 -67182.87 -64297.36
>>>
>>>
>>> Ekrem Kalkan
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>>
>>
>>
>> --
>> Steven Samuels
>> [email protected]
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>
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