# [R-sig-ME] fitting method in glmer and var for the cond. modes

vito muggeo vmuggeo at dssm.unipa.it
Fri Jan 11 11:39:42 CET 2008

dear all,
I 've just installed the last version of lme4.
Thanks to prof Bates for his excellent work.

I have an issue and a question.

1)issue:
I tried to fit binomial GLMM, everything works but it appears that the
method="PQL" is not implemented..Namely the following two calls yield
exactly the same results
glmer(formula,family=binomial,data=d,method="Laplace")
glmer(formula,family=binomial,data=d,method="PQL")

The summary method on the relevant fits prints in each case (correctly?)
Generalized linear mixed model fit by the Laplace approximation''

The estimates are very similar to those coming from MASS::glmmPQL(). For
instance the est. st.dev for the interc is 0.1613318 (via glmmPQL()) vs.
0.16119 (via glmer()+laplace). Since the response is binary, I expected
the estimates to be somewhat different..

2)question:
I am interested in obtaining the variances of the predictions (i.e. the
variances of conditional modes \tilde{b}_i) from a simple LMM (fitted
via lme or lmer)

As far as I remember correctly, there was the bVar' slot in the early
versions of lmer..Am I right?

Also, how I can extract the same quantities from a "lme" fits?

many thanks,
vito

--
====================================
Vito M.R. Muggeo
Dip.to Sc Statist e Matem Vianelli'
Università di Palermo
viale delle Scienze, edificio 13
90128 Palermo - ITALY
tel: 091 6626240
fax: 091 485726/485612