[R-sig-ME] Fwd: [Lme4-authors] LME4 and Lmer model
bbolker at gmail.com
Wed Oct 1 02:15:19 CEST 2014
Ken Beath <ken.beath at ...> writes:
> The BY statement in SAS has nothing to do with BLUP, it simply runs an
> analysis separately for each group defined by BY. The empirical BLUP
> predicts the values of the random effect for each group taking into
> consideration all the data.
> There is a command in SAS for extracting the random effect predictions
> which I would hope gives the same results as ranef in R.
For what it's worth, in addition to the variety of different
packages that provide generic strategies for dealing with grouped data
in R (plyr::ddply, dplyr::group_by, data.table ...), lme4 has an
lmList() function (as does nlme -- they're almost but not quite
compatible/identical) for this specific task (fitting linear models
to each of a variety of groups).
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