RE: st: How to add restriction condition in Stata

[Richard Williams <Richard.A.Williams.5@ND.edu>]

At 12:07 PM 7/29/2005 -0500, FEIVESON, ALAN H. (AL) (JSC-SK) (NASA) wrote:
> I still don't see why you can't sum the ages. What's the difference between:
>
> y ~ Poisson(la); log la = b0 + b1*age1 + b2*age2  with b1=b2
>
> and
>
> y ~ Poisson(la); log la = b0 + b1*(age1+age2) ?
>
>
> Al Feiveson
I agree with Alan.  Also I am not sure if this solves the problem - you can 
impose constraints but they have to make sense, i.e. the effect of age1 
really does have to equal the effect of age2.  Just curious, is this 
approach based on published research?  If so I'd be interested in looking 
at it.


-------------------------------------------
Richard Williams, Notre Dame Dept of Sociology
OFFICE: (574)631-6668, (574)631-6463
FAX:    (574)288-4373
HOME:   (574)289-5227
EMAIL:  Richard.A.Williams.5@ND.Edu
WWW (personal):    http://www.nd.edu/~rwilliam
WWW (department):    http://www.nd.edu/~soc

*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/