Re: st: twoway graph for imututed values against observed

[Andrew Stoddart <andrew.stoddart@ed.ac.uk>]

Thanks Wesley,

A slightly adapted version of your code seems to have done the trick.

Thanks also to Maarten for his help.

Andy



Quoting "Wesley D. Eddings, StataCorp" <weddings@stata.com> on Wed, 25  
Jan 2012 17:40:44 -0600:

> Andy Stoddart (andrew.stoddart@ed.ac.uk) asked about checking the imputations
> created by -mi ice-:
>
> > Does anyone know of a way to graph the imputed values over the  
> > observed values
> > on the same graph?
>
> > For example I am at present using
>
> > mi set wide
> > mi ice ? , add(5) [options]
>
> > twoway (hist x1, [options]) (hist _1_x1 if missing(x1), [options]), ///
> > legend(label(1 "observed") label(2 "imputed"))
>
> > I then view each of the 5 imputations by swapping  _1_x1   for
> > _2_x1, _3_x1, _4_x1 and _5_x1 in turn to quickly check the imputed
> > values appear reasonable
>
> > Obviously it would be preferable to be able to plot all imputed values
> > against all observed directly rather than checking individual
> > imputations one at a time.
>
> It is possible to use -mi xeq-, rather than repeatedly changing the  
> name of the
> variable to be graphed.  Here are the commands to make Andy's plots  
> for all five
> imputations:
>
>
> . generate byte miss_x1 = missing(x1)
> . qui mi xeq 1/5: twoway (hist x1 if miss_x1==0) ||   ///
>    (hist x1 if miss_x1==1),     ///
>    legend(label(1 "observed") label(2 "imputed")); ///
>    set more on; more; set more off
>
> It's safe to -generate- the "miss_x1" variable because Andy is using  
> the -wide-
> -mi- style.  I took the commands from the note on multiple-imputation
> diagnostics, which includes other plots Andy might find useful.  The note is
> available at
>
> http://www.stata.com/users/ymarchenko/midiagnote.pdf
>
> It is usual to check each imputed dataset separately.  I do not know of any
> research on comparing the aggregate of the observed data to the  
> aggregate of the
> imputed values.
>
>
> --Wes
> weddings@stata.com
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Andy Stoddart
Health Economist
Edinburgh Health Services Research Unit (HSRU)
www.hsru.ed.ac.uk

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