[R] negative AIC and BIC values in gls

[Bert Gunter]

Inline.



On Wed, Aug 22, 2012 at 5:17 PM, Jeremy Miles <jeremy.miles at gmail.com> wrote:
> It's fine. Just interpret them as you would any other (lower is better).
>
I don't think so. I believe all 3 values are the negative of what they
should be. AIC is defined as -2*log(L) + k*{degrees of freedom for
model) . BIC is similar (different k's). This should be positive and,
as you said, the smaller the better. So if the signs are reversed,
models with lower absolute AIC and BIC -- bigger negative AIC and BIC
-- is what you want.

However, this really needs comment by an expert, which I ain't. I also
suggest you post to r-sig-mixed-models, since gls is an nlme function.

Cheers,
Bert

>
> On 22 August 2012 16:43, Gary Dong <pdxgary163 at gmail.com> wrote:
>> Dear R users,
>>
>> I obtained negative AIC and BIC and positive Loglik values in a gls model.
>> Is this normal? how should I interpret them? Thanks!
>>
>>        AIC       BIC           logLik
>>   -659.978  -587.5541   345.989
>>
>> Best
>> Gary
>>
>>         [[alternative HTML version deleted]]
>>
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>> and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.



-- 

Bert Gunter
Genentech Nonclinical Biostatistics

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