R help - Mar 2009 - set intercept in glm to non-0

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

Use an offset with a non-intercept model?

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

--  
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

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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> and provide commented, minimal, self-contained, reproducible code.
>
Thomas Lumley			Assoc. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle