Re: st: Including components of a summative score in regression

[Donald Spady <dspady@ualberta.ca>]

Maarten
  Thanks for the reference.  I'll try and get it at my University library.  
Don 
On 2012-07-31, at 1:35 AM, Maarten Buis <maartenlbuis@gmail.com> wrote:

> At 02:46 PM 7/30/2012, Donald Spady wrote:
>>> I am doing some logistic regression analysis, some of the variables of
>>> which are made up of the values of other variables; e.g. N = A + B + C/D.
>>> Is it reasonable, or appropriate, to include A,  B, C, or D in the
>>> equation if N is already in it.
> 
> On Mon, Jul 30, 2012 at 11:12 PM, Richard Williams wrote:
>> I believe the improvements in fit stem from
>> 
>> * N constrains the coefficients of A and B and C/D to be equal; adding A and
>> B relaxes two of those constraints.
> 
> Also see:
> M.L. Buis (2012) "Stata tip 108: On adding and constraining", The
> Stata Journal, 12(2), pp. 342-344.
> 
> Hope this helps,
> Maarten
> 
> --------------------------
> Maarten L. Buis
> Institut fuer Soziologie
> Universitaet Tuebingen
> Wilhelmstrasse 36
> 72074 Tuebingen
> Germany
> 
> 
> http://www.maartenbuis.nl
> --------------------------
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Donald Spady

--
dspady@ualberta.ca





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