Hi Sam, I don't understand how you can estimate a separate id variance other than the residual variance, with one observation per subject. I would think the proper model would be glm(y ~ 1, family='poisson) Cheers, Hank
On Oct 15, 2007, at 12:05 PM, Sam Field wrote: > Group, > > I have count data with one observation per subject. I would like > to fit > a glmm to these data in order to account for overdispersion in the > outcome. The lmer() function does not appear to be able to handle data > that have only one observation per-cluster id, even though separate > variance components for the count and normal portions of the > outcome are > identifiable. The glmmML() function does not seem to have problems > with > this (as the code below illustrates). > > library(lme4) > library(glmmML) > u <- rnorm(100) > y <- rpois(100,exp(u)) > id <- seq(1:100) > summary(glmmML(y~1,cluster=as.factor(id),family =poisson)) > summary(lmer(y~1+(1|id),family='poisson')) > > I would like to use lmer() rather then glmmML(). Does anybody know > of a > way of getting the lmer() function to work with these kinds of data? > > Sam > > > -- > Samuel H. Field > Division of Internal Medicine - University of Pennsylvania > CHERP - Philadelphia VA Medical Center > 3900 Woodland Ave (9 East) > Philadelphia, PA 19104 > (215) 823-5800 EXT. 6155 (Office) > (215) 823-6330 (Fax) > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting- > guide.html > and provide commented, minimal, self-contained, reproducible code. Dr. Hank Stevens, Associate Professor 338 Pearson Hall Botany Department Miami University Oxford, OH 45056 Office: (513) 529-4206 Lab: (513) 529-4262 FAX: (513) 529-4243 http://www.cas.muohio.edu/~stevenmh/ http://www.muohio.edu/ecology/ http://www.muohio.edu/botany/ "E Pluribus Unum" If you send an attachment, please try to send it in a format anyone can read, such as PDF, text, Open Document Format, HTML, or RTF. Please try not to send me MS Word or PowerPoint attachments- Why? See: http://www.gnu.org/philosophy/no-word-attachments.html ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
