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

[Edwin Leuven <e.leuven@uva.nl>]

fatma bircan wrote:
> 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? 
i suggest you read chapter 16 of:

http://mitpress.mit.edu/wooldridge-EconAnalysis

it explains very clearly the issues, and how you should properly 
calculate partial effects in corner solution models like yours


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