Re: st: Missingness

[Richard Williams <richardwilliams.ndu@gmail.com>]

At 02:42 AM 8/28/2012, Brendan Churchill wrote:
> Dear Statalist Users
>
> I am using some ordinal variables, which have some numeric missing 
> values, in a multilevel model. In some previous research, I have 
> seen researchers include a 'Missing' independent variable in their 
> model to account for some of the 'missingness' - or rather to 
> control for the missing values, but I don't quite understand how to 
> do it in Stata or even if that's a good way to do it. I've tried to 
> make a binary variable in which the missing values are coded 1 and 
> the rest of the values are coded 0 but the model rejects this 
> because it's collinear.
> Is this how you do it? Or is there a variable for the entire data 
> set that is created to account for all missing variables?
In his green Sage book, "Missing Data", Paul Allison explains why 
this is usually (albeit not always) a bad idea. I briefly summarize 
the argument on pp. 4-5 of
http://www.nd.edu/~rwilliam/xsoc63993/l12.pdf

-------------------------------------------
Richard Williams, Notre Dame Dept of Sociology
OFFICE: (574)631-6668, (574)631-6463
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EMAIL:  Richard.A.Williams.5@ND.Edu
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