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RE: st: Calculation of cubic splines


From   Nick Cox <n.j.cox@durham.ac.uk>
To   "'statalist@hsphsun2.harvard.edu'" <statalist@hsphsun2.harvard.edu>
Subject   RE: st: Calculation of cubic splines
Date   Thu, 19 May 2011 15:27:31 +0100

Pessimistic answer: Seems to me that you want to echo what Stata does without doing it directly in Stata. In this case that is at least difficult. 

Optimistic answer: You must plug coefficients and data into the RHS of the correct logit equation. 

At this point, fractional polynomial people would be saying that you'd better off using fractional polynomials. 

Nick 
n.j.cox@durham.ac.uk 

Mikkel Brabrand

But is predict not a post estimation command? How can I then use the same weights? Sorry if this is a stupid question but I have spend a frustrating looooong time on this!

Den 19/05/2011 kl. 16.14 skrev Maarten Buis:

> On Thu, May 19, 2011 at 4:09 PM, Mikkel Brabrand <mikkel@brabrand.net> wrote:
>> Thanks!  What I need to do is recalculate the predicted probabilities in a different dataset using the same weights. That is why I am trying to figure out the formula...
> 
> Just use -mkspline- to create the variables, using the -knots()-
> option to set the knots at the same values as in your original
> dataset. Than you can just use -predict-.


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