[R] I am struggling with contrasts

[peter dalgaard]

Yes. Contrasts, by definition, represents between-group differences, so cannot yield individual group levels. The closest you get is that the _intercept_ is the level of the base group in treatment contrasts, and relevel() will allow you to change the base level.

-pd

> On 10 Mar 2020, at 04:06 , Berwin A Turlach <Berwin.Turlach using gmail.com> wrote:
> 
> G'day John,
> 
> On Tue, 10 Mar 2020 01:42:46 +0000
> "Sorkin, John" <jsorkin using som.umaryland.edu> wrote:
> 
>> I am running a Poisson regression with a single outcome variable,
>> HGE, and a single independent variable, a factor, Group which can be
>> one of two values, Group1, or Group2. I am trying to define contrasts
>> that will give me the values of my outcome variable (HGE) when
>> group=Group1 and when group=Group2. 
> 
> Not sure what you mean, but I am suspecting you are after this output:
> 
> R> fit0 <- glm(HGE ~ Group - 1,family=poisson,data=dataForR,offset=logFU)
> R> summary(fit0)
> 
> Cheers,
> 
> 	Berwin
> 
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-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
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