[R] set intercept in glm to non-0

Thomas Lumley tlumley at u.washington.edu
Tue Mar 17 08:54:23 CET 2009


On Mon, 16 Mar 2009, David Winsemius wrote:

>
> Use an offset with a non-intercept model?

Yes

dat$ones<-1
glm(y~0+x+offset(ones), data=dat, family=whatever)

> I wonder if there could be problems depending on the choice of family.

Only in the sense that if the model fits badly it might run up against the edge of the parameter space in some families, which is no different than the potential problems with a zero intercept.

       -thomas


>
> -- David Winsemius
>
> On Mar 16, 2009, at 9:29 PM, Peter Palenchar wrote:
>
>> 	I know how to make the intercept 0 in glm, but I actually want to force my 
>> intercept to be 1.  Is there a way I can do this?
>> 
>> Peter
>> 
>> and provide commented, minimal, self-contained, reproducible code. .... 
>> (None provided)
>
> David Winsemius, MD
> Heritage Laboratories
> West Hartford, CT
>
> ______________________________________________
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

Thomas Lumley			Assoc. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle




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