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Re: st: RE: ln1=0 for missing values


From   fatma bircan <bircan@metu.edu.tr>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: RE: ln1=0 for missing values
Date   Wed, 21 Apr 2004 15:40:38 +0300

For example in a Tobit model if we make a log transformation of the
expenditures (dep. var.) some values of the dep. var. will have
missing values since they were originally equal to zero. But assuming
that the zero exp. =1 and then taling the log of expenditures, we can
estimate the tobit model. Is this OK for having extra grouns? 


-------------------
>Yes, there are. Unless you have extra grounds
>for thinking that missing really means 1, 
>this practice surely cannot be recommended 
>in general. 
>
>Nick 
>n.j.cox@durham.ac.uk 
>
>fatma bircan
> 
>> Is there any problems with assuming that the dependent variable
takes
>> the value of 1 when it is missing to make the ln(dep. var.) equal
to
>> zero.
>
>*
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>
Fatma Bircan
Middle East Technical University
Department of Economics
210-2032



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