[Gretl-users] Constant in log-likelihood

Alecos Papadopoulos papadopalex at aueb.gr
Wed Jul 10 12:18:08 EDT 2013


In model 1 (without the constant in the log-l), the value of the 
maximized log-likelihood is -447.
If one wants to arrive at the actual full value of the log-likelihood 
one should add to this nobs*ln(4/sqrt(2/$pi)) = 595*0.46.. = 274, and 
obtain -447 + 274 = -173.

Now in model 2, parameter estimates are virtually identical with model 
1, so one would expect that, since here the constant is already included 
in the  logl eq., it would arrive at a comparable result with the 
corrected full value (i.e. -173),  and not +511, which is the value for 
the logl given by the code in model 2.

Alecos Papadopoulos
Athens University of Economics and Business, Greece
Department of Economics
cell:+30-6945-378680
fax: +30-210-8259763
skype:alecos.papadopoulos

On 10/7/2013 19:00, gretl-users-request at lists.wfu.edu wrote:

> ------------------------------ Message: 2 Date: Wed, 10 Jul 2013 
> 09:05:57 +0200 (CEST) 

> From: "Riccardo (Jack) Lucchetti" <r.lucchetti at univpm.it> 

> Subject: Re: [Gretl-users] Graph two densities together and Constant 
> in Log Likelihood To: Gretl list <gretl-users at lists.wfu.edu> 

> Message-ID: <alpine.DEB.2.10.1307100904510.23263 at ec-4.econ.univpm.it> 
> Content-Type: text/plain; charset="iso-8859-15" On Wed, 10 Jul 2013, 

> Alecos Papadopoulos wrote:
>> Just a note that
>> in model 2 (that is virtually identical to model 1 as regards to
>> estimates and final gradient values), the value of the logl appears
>> positive.
> Since you add a positive constant to each observation, why would that be
> surprising?
>
> -------------------------------------------------------
>     Riccardo (Jack) Lucchetti
>     Dipartimento di Scienze Economiche e Sociali (DiSES)
>
>     Universit? Politecnica delle Marche
>     (formerly known as Universit? di Ancona)
>
>     r.lucchetti at univpm.it
>     http://www2.econ.univpm.it/servizi/hpp/lucchetti
> -------------------------------------------------------
>
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> End of Gretl-users Digest, Vol 78, Issue 12
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