[R-sig-ME] REML vs ML in lmerTest

[Bradley Carlson]

The package is lmerTest, the function is anova within that package. I can't
find anyway to determine whether it is re-estimating the model (it doesn't
report anything about REML or ML). If it was re-estimating, though, then
the sums of squares shouldn't be different between the two - but they are.

On Tue, May 5, 2015 at 2:19 PM, Daniel Wright <Daniel.Wright at act.org> wrote:

> Check if the lmerTest function re-estimates the model with ML.  Not sure
> what lmerTest function you are using (which package?).
>
> -----Original Message-----
> From: R-sig-mixed-models [mailto:r-sig-mixed-models-bounces at r-project.org]
> On Behalf Of Bradley Carlson
> Sent: Tuesday, May 05, 2015 1:15 PM
> To: r-sig-mixed-models at r-project.org
> Subject: [R-sig-ME] REML vs ML in lmerTest
>
> Hi everyone,
>
> I'm a little confused about the use REML and ML. I fit models in lmer,
> which were pretty straightforward (a few continuous and a few nominal
> predictors, plus random intercepts for clusters of data). I tested the
> fixed effects using the lmerTest anova function with Kenward-Roger df (I
> have no interest in testing random effect significance). I get the same F
> values, df, and p values regardless of whether the models were fit with
> REML or ML, but the actual sums of squares in the anova output differ
> modestly. Given that it didn't matter at all for the results, it doesn't
> seem I should particularly care whether I use REML and ML in the lmer. But,
> I want to report which I used.
>
> So my questions:
>
> -Why do I get the same statistical values except for SS with REML and ML?
> -Which would be more appropriate - REML or ML? I'm thinking REML because I
> have an unbalanced sample sizes for each level of the random effect (based
> on Bolker et al. 2008), but I wanted to double check that this makes sense.
>
> Thank you!
> Brad
>
> --
>
> Bradley Evan Carlson
> Assistant Professor of Biology
> Wabash College, Crawfordsville IN
>
> Email: *carlsonb at wabash.edu* <+carlsonb at wabash.edu>
> Website: https://sites.google.com/site/bradleyecarlson/home
>
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-- 

Bradley Evan Carlson
Assistant Professor of Biology
Wabash College, Crawfordsville IN

Email: *carlsonb at wabash.edu* <+carlsonb at wabash.edu>
Website: https://sites.google.com/site/bradleyecarlson/home

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