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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