[R-sig-ME] lmer vs. nlme

[Thierry Onkelinx]

Dear Ashley,

Please add some (reproducible) examples. Without that we can only guess
which models you fitted and why the results are identical. Please do add
the output of sessionInfo() as well.

Best regards,


ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature and
Forest
team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance
Kliniekstraat 25
1070 Anderlecht
Belgium

To call in the statistician after the experiment is done may be no more
than asking him to perform a post-mortem examination: he may be able to say
what the experiment died of. ~ Sir Ronald Aylmer Fisher
The plural of anecdote is not data. ~ Roger Brinner
The combination of some data and an aching desire for an answer does not
ensure that a reasonable answer can be extracted from a given body of data.
~ John Tukey

2016-01-18 21:20 GMT+01:00 Ashley Cohen <ashleyhcohen op gmail.com>:

> Hi Mixed Models group;
>
>
>
> I was wondering if you might be able to clarify some confusion I am having
> with results from lmer.
>
>
>
> I am running a mixed model with fixed effects for treatment, time and an
> interaction between treatment and time. A random effect has been added in
> for subject (for repeated measures).
>
>
>
> I was under the impression, based on the response from Ben Bolker here,
> that lmer would be estimating an unstructured correlation matrix:
>
>
> http://stats.stackexchange.com/questions/86958/variance-covariance-structure-for-random-effects-in-glmer
>
>
>
> However, when I ran the model with lme, specifying a compound symmetric
> correlation structure and random effect, I got the exact same results as
> from lmer.
>
>
>
> I am not sure about what is going on and was wondering if you had any
> thoughts on this. I also couldn’t find a way to pull out the correlation
> matrix from lmer.
>
>
>
> Thank you,
>
>
> Ashley
>
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>
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