Hello, I'm trying to run an lmer model with family poisson but receive the following warning message: model<-lmer(count~tem+dat+alt+year+tem:dat+tem:alt+tem:year+dat:alt+dat:year+alt:year+(1|id),family=poisson) Error in objective(.par, ...) : Leading minor of order 2 in downdated X'X is not positive definite I'm using the newest version of R and recently installed the following libraries: (lme4, matrix, lattice). I don't understand what the warning message means or know how to fix it, please help! My response variable is a count variable (n=551); 212 with value = 0, and the rest range between 1-3. -- View this message in context: http://www.nabble.com/warning-message-for-lmer-model-with-poisson-family-tp17659512p17659512.html Sent from the R help mailing list archive at Nabble.com.
Steven McKinney
2008-Jun-05 03:35 UTC
[R] warning message for lmer model with poisson family
Looks like you have some independent variables in your model that correlate perfectly so your design matrix is not of full rank, probably because your independent variable data is not balanced. Does a simpler fit such as model<-lmer(count~tem+(1|id),family=poisson) give you a result? You might need to build up your model from such a simple one, adding one new term at a time until you find the one that causes the issue. You probably do not have enough balanced data to allow fitting such a complex model. HTH Steve McKinney -----Original Message----- From: r-help-bounces at r-project.org on behalf of arams Sent: Wed 6/4/2008 5:18 PM To: r-help at r-project.org Subject: [R] warning message for lmer model with poisson family Hello, I'm trying to run an lmer model with family poisson but receive the following warning message: model<-lmer(count~tem+dat+alt+year+tem:dat+tem:alt+tem:year+dat:alt+dat:year+alt:year+(1|id),family=poisson) Error in objective(.par, ...) : Leading minor of order 2 in downdated X'X is not positive definite I'm using the newest version of R and recently installed the following libraries: (lme4, matrix, lattice). I don't understand what the warning message means or know how to fix it, please help! My response variable is a count variable (n=551); 212 with value = 0, and the rest range between 1-3. -- View this message in context: http://www.nabble.com/warning-message-for-lmer-model-with-poisson-family-tp17659512p17659512.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help at 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.