I'm a bit late to the game on this one, but I would second the votes for
flexible covariance structures as in nlme. Perhaps this could be done by
investing funds into the flexlambda work?
Regarding two other suggestions:
1. Julia-like speed. There are bridges between Julia and R, but this
still doesn't help me once I have a fitted model in Julia and want the R
mixed-models ecosystem (effects, car::Anova(), lmerTest, etc.) to
examine the model. It should however be possible to construct a merMod
object from the fit in Julia. Tools for doing this would be quite nice.
(This also seems like relatively low-hanging fruit for a Google summer
of code type project.)
2. Better confidence intervals and predictions for non-linear links. I
think some parts of this are implemented in the effects and emmeans
packages. In addition to a more extensive/complete implementation, this
seems like something where additional documentation and worked examples
comparing conditional and marginalized coefficients would be useful,
potentially as part of the GLMM FAQ.
Best,
Phillip
Post by Manuel RamonI totally agree with you, Ben. I have to admit that all the tidyverse world
has suppose a great improvement in the way I work with data, but in the
end, almost all my analyses conclude with the nlme/lme4 packages. So I
think it is worth investing funds and time on it.
As suggested by others, the inclusion of the variance functions from nlme
would be very useful. Also, some of the capabilities of the mixed.models in
Julia language in terms of computation time and data size would be very
welcome, but this latter it is probably very difficult (almost impossible)
given that they are to different platforms.
In any case, thanks for the initiative and I hope it will go ahead.
Regards,
Manuel
Post by Ben Bolkerhttps://www.r-consortium.org/announcement/2018/09/25/fall-2018-isc-call-for-proposals
"What can you do to improve the R ecosystem and how can the R Consortium
help you do it?"
The mixed-model ecosystem is admittedly a small part of the R
ecosystem, but I (biasedly) think it's an important one.
If people have ideas & opinions about how a chunk of money on the
order of $10,000 could be valuably spent to improve the mixed-model
ecosystem in a way that would be appealing to a very broad audience of
useRs, please discuss.
The deadline for submitting a proposal is midnight PST, Sunday October
31, 2018.
cheers
Ben Bolker
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