Hi Philippe,
Amelia uses a linear model to do the imputation, so it treats all variables
as continuous and ordered. Thus, you want to use similar approaches to
controls for a linear model. If you have a nominal variable, you are better
off naming it as so since Amelia will then convert the nominal to the
correct series of binary variables so that the linear model more
approximately holds. Ordinal variables are less of a problem.
Cheers,
matt.
~~~~~~~~~~~
Matthew Blackwell
Assistant Professor of Political Science
University of Rochester
url:
http://www.mattblackwell.org
On Tue, Sep 4, 2012 at 1:16 PM, Philippe Sulger <philippe.sulger(a)econ.uzh.ch
wrote:
> I should ask all included into the amelia-list:
> I have already run imputations without these specifications for the
> auxiliary variables. The question is now of whether I should rerun, or more
> specifically, what might be critical points when it comes to answering that
> question?
>
> Thank you for your help.
>
> Philippe
>
>
> On 04.09.12 16:43, Gary King wrote:
>
> you're specifying a model, and that model includes all the variables that
> go into Amelia and so can affect your imputations. which is the right
> thing to do in any one case of course more debatable...
> Gary
> --
> *Gary King* - Albert J. Weatherhead III University Professor - Director, IQSS
> <http://iq.harvard.edu/>- Harvard University
>
GKing.Harvard.edu <http://gking.harvard.edu/> - King(a)Harvard.edu -
> @kinggary <http://twitter.com/kinggary> - 617-500-7570 - Asst 495-9271 -
> Fax 812-8581
>
>
>
> On Tue, Sep 4, 2012 at 11:35 AM, Philippe Sulger <
> philippe.sulger(a)econ.uzh.ch
wrote:
>
>> Dear Amelia-Users
>>
>> I run imputations with some auxiliary variables that are nominal or
>> ordinal. Do I have to classify them as ordinal or nominal for the
>> imputation, or is it sufficient only to classify the variables of interest
>> to be be nominal or ordinal? In other words: does it affect the quality of
>> imputation in any sense if I don't classify them?
>>
>> Thank you for your efforts.
>>
>> Best,
>> Philippe
>>
>> --
>> ===============================================================
>> Philippe Sulger
>> Visiting Scholar
>>
>> Institute of Criminology
>> Sidgwick Avenue
>> University of Cambridge
>> CB3 9DA Cambridge, UK
>> ===============================================================
>> Email: philippe.sulger(a)econ.uzh.ch
>> ps596(a)cam.ac.uk
>>
>> Web:
http://www.econ.uzh.ch/faculty/sulger.html
>>
http://www.crim.cam.ac.uk/people/visitors/philippe_sulger
>> ===============================================================
>>
>>
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>
>
> --
> ===============================================================
> Philippe Sulger
> Visiting Scholar
>
> Institute of Criminology
> Sidgwick Avenue
> University of Cambridge
> CB3 9DA Cambridge, UK
> ===============================================================
> Email: philippe.sulger(a)econ.uzh.ch
> ps596(a)cam.ac.uk
>
> Web:
http://www.econ.uzh.ch/faculty/sulger.html
>
http://www.crim.cam.ac.uk/people/visitors/philippe_sulger
> ===============================================================
>
>
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