[R-sig-ME] Problem- Warning message

[Ken Beath]

There are two random effects, another one for obs which is modelling
overdispersion.

It looks like the optimizer has decided to stop, but has stopped when the
gradients are not zero, that is it is not a maxima. It could just be the
numerical gradients are a problem, but it could be something else. I've
been having similar trouble with a glmm, and it seems to be a problem with
the way glmer does something.

I don't know how much data that you have, but it is possible that your
model is just too complex for the data available. The first rule of these
models is to start with something simple and then add to the model until
something breaks, then you can think about why it broke.

On 27 February 2015 at 04:14, Davide Bellone <bellonedavide1 at gmail.com>
wrote:

> Goodevening,
>
> this is my first mail . From what a collegue told me I can ask to the
> members of this mailing list to help me with my problem.
> So, what I am trying to do is a glmer model. I have 1 random effect (Site)
> and 6 fixed effects.
>
> Model <- read.table("c:\\TXT X R\\Tabella modello gruppi
> completo.txt",header=T)
> y <- cbind(Model$Rem, Model$Total-Model$Rem)
> Model$wood <- as.factor(Model$wood)
> Model$under <- as.factor(Model$under)
> Model$Manage <- as.factor(Model$Manage)
> Model$Size <- as.factor(Model$Size)
> Model$Site <- as.factor(Model$Site)
> obs <- 1:length(Model$Site)
> obs
> options(contrasts=c("contr.sum", "contr.poly"))
> R1 <- glmer(y ~ Model$Manage + Model$age +  Model$veg + Model$Size +
> Model$wood + Model$under + Model$age*Model$Manage + Model$veg*Model$Manage
> + (1|Model$Site)+(1|obs) , family= binomial)
>
> The first output is:
> Warning message:
> In checkConv(attr(opt, "derivs"), opt$par, ctrl = control$checkConv,  :
>   Model failed to converge with max|grad| = 1.02046 (tol = 0.001, component
> 3)
>
> Can someone explain if there is some problem in data and if there is a
> solution?
>
> Thank you. I hope that my collegue told me the right way to how to use the
> mailing list
>
> Dävide
>
>         [[alternative HTML version deleted]]
>
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-- 

*Ken Beath*
Lecturer
Statistics Department
MACQUARIE UNIVERSITY NSW 2109, Australia

Phone: +61 (0)2 9850 8516

Building E4A, room 526
http://stat.mq.edu.au/our_staff/staff_-_alphabetical/staff/beath,_ken/

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