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Re: st: RE: Imputed Missing Values with Uvis
At 10:03 PM 2/24/2005 +0000, you wrote:
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.
You seem surprised at this.
If you don't know -x1-, you cannot
predict -y- from -x1 x2 x3-; and
If you do know -y- you don't need
to impute it.
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
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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