Re: st: Trying to do some multiple imputation

[Rose Medeiros <rosem@cisunix.unh.edu>]

Mosi,
If your goal is just to impute values of your income variable, you might 
use -uvis- which will impute values of the yvar and leave them in your 
initial dataset. If this is problematic because of a large number of 
missing values in the variables you are attempting to impute income 
from, you could use -mvis- and generate only one imputation by 
specifying m(1) and run your analyses on this dataset (which would also 
have imputed values for the other variables). Note that both of these 
procedures are single imputation, rather than multiple imputation. If 
you actually want to do multiple imputation, you would want to use 
-micombine- to specify the actual models you want to test, not the 
variables you are trying to impute.
Best,
Rose

Mosi A. Ifatunji wrote:


> Good people,
>
> Here is my quandary. I am having a heck of a time trying to complete
> procedures for multiple imputation using Stata 8.2.
>
> My goal is to impute missing values for my income variable (v1019). I would
> like to generate 5 new and complete datasets from which to derive my new
> values (to be placed back into the old dataset). Here is the syntax I have
> been using to no avail:
>
> First, I use the MVIS command to generate five new datasets with values for
> any missing values in the key variables:
>
> mvis v1019 black male age2 educate using imp, m(5) genmiss(m_) cmd(regress)
> cy(20) se(101) replace
>
> And I get...
>
> imputing 1..2..3..4..5..file imp.dta saved
>
> Then, I open the new dataset (with all missing values imputed):
>
> use imp, clear
>
> Then I generate a model (from the 5 new datasets in imp.dta) that predicts
> my income variable (v1019):
>
> micombine regress v1019 black male age2 educate
>
> Multiple imputation parameter estimates (5 imputations)
> ----------------------------------------------------------------------------
>   v1019 |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
> -------------+-------------------------------------------------------------
>   black |  -16060.96   2412.319    -6.66   0.000    -20794.22    -11327.7
>    male |   10331.52   2487.338     4.15   0.000     5451.057    15211.97
>    age2 |  -114.4879   90.15501    -1.27   0.204    -291.3829    62.40716
> educate |   4532.232    722.751     6.27   0.000     3114.107    5950.357
>   _cons |  -8530.671    12416.8    -0.69   0.492    -32893.94     15832.6
> ----------------------------------------------------------------------------
> 1106 observations.
>
> Now what do I do? I have been roaming through manuals and copies of the
> Stata Journal (4-3 and 5-4) but every time to get near, the author(s) leave
> out something important, like how exactly do I use MISET, MI SPLIT AND
> MIJOIN to get my imputed values back to my original dataset....
>
> Any help would be greatly appreciated...
>
> M.
>
>
> *
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>
>  

--
Rose Anne Medeiros
Department of Sociology / Family Research Laboratory
University of New Hampshire
126 Horton Social Science Center
20 College Road
Durham, NH 03824
U.S.A.

*
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