Re: st: RE: Imputed Missing Values with Uvis

[Richard Williams <Richard.A.Williams.5@nd.edu>]

At 10:03 PM 2/24/2005 +0000, you wrote:
> You seem surprised at this.
>
> If you don't know -x1-, you cannot
> predict -y- from -x1 x2 x3-; and
> so on.
>
> If you do know -y- you don't need
> to impute it.
If I understand Quang correctly, then the latter is exactly the point. 
-uvis- should have just plugged in the observed value for y rather than 
even try to impute it; but instead, it plugged in a missing value since one 
or more of the Xs for that case was missing.

I tried -uvis- on a data set where y was not missing but some values of x 
were.  The generated y had missing data whereas the original y did not.

I'm not that familiar with the programs but if nothing else one work around 
might be

replace uvis_y = max(original_y, uvis_y)

where uvis_y is the var generated by uvis. If I've done this correctly, 
then whenever -uvis- generated an unnecessary MD code for y, the original 
non-missing value for y will get plugged back in.

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