[R] repeated measures nonlinear regression

Douglas Bates bates at stat.wisc.edu
Mon Feb 16 13:56:30 CET 2004

Wayne Hallstrom <wayne.hallstrom at ualberta.ca> writes:

> I found this email on the R website.  I am trying to figure out how
> to analyse a data set that I believe will need to be run through a
> procedure involving repeated measures, regression and mixed models.
> The data is of insect populations (dependent variable - either
> 0/1=binomial, or as counts=poisson) in sites with different
> characteristics (multiple independent variables which are both
> categorical and continuous).  These populations were repeatedly
> sampled (an unequal number of times) at different times during the
> year.
> The standard stats packages are not able to do what I would like to
> do.  Any suggestions for some alternative methods such as those
> which are specially programmed for R and are suited to the type of
> data which I am analysing?  I understand I will need a flexible
> repeated measures application to be able to accept the unequal
> sampling.  I also will need a gnlm regression to fit the general
> data structure.  And also, I think, the mixed models capability in
> order to fit in the true nature of the data (see next paragraph).

It sounds like you should be fitting a generalized linear mixed
model.  Look for the functions GLMM in package lme4 or glmmPQL in
package MASS.

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