[R-sig-ME] [R] lme4 and false convergence

ONKELINX, Thierry Thierry.ONKELINX at inbo.be
Tue Nov 25 10:35:43 CET 2008

Dear Ben,

Your questions suite better in R-SIG-Mixed-Models which I am cc'ing.
Have checked the mailing list? Try RSiteSearch("lme4 false convergence")



ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature
and Forest
Cel biometrie, methodologie en kwaliteitszorg / Section biometrics,
methodology and quality assurance
Gaverstraat 4
9500 Geraardsbergen
tel. + 32 54/436 185
Thierry.Onkelinx at inbo.be 

To call in the statistician after the experiment is done may be no more
than asking him to perform a post-mortem examination: he may be able to
say what the experiment died of.
~ Sir Ronald Aylmer Fisher

The plural of anecdote is not data.
~ Roger Brinner

The combination of some data and an aching desire for an answer does not
ensure that a reasonable answer can be extracted from a given body of
~ John Tukey

-----Oorspronkelijk bericht-----
Van: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
Namens Ben Zuckerberg
Verzonden: maandag 24 november 2008 18:37
Aan: r-help at r-project.org
Onderwerp: [R] lme4 and false convergence

Dear R-users,

I am using the most updated package of lme4 (lme4_0.999375-2).  I have a

data set consisting of ~900 observations at ~440 independent survey 
sites.  There are an unbalanced number of surveys at each site.  I am 
attempting to develop several models evaluating the presence/absence of 
a species (PRES) at these random sites (SITE) using a number of 
predictor variables.  The response variable (PRES) is binomial and the 
included predictor variables are either proportions (e.g., AG, FOR, 
OPEN, LDEV,or DEV) or numerical (COUNT[min. 1 to max. 37,mean = 10]). 

I have developed the following GLMM:


I receive the following error:
Warning message:
In mer_finalize(ans) : false convergence (8)

There is model output, but I am worried it might be biased. 

I have tried:
-Data transformation of the predictor variables (e.g., log(COUNT)), 
which does seem successful in some simpler models, but does not work 
-The most updated version of lme4

In addition, I am interested in visualizing the predicted probabilities 
from this output using the fixed effect function, but receive the 
following message:

Error in UseMethod("fixef") : no applicable method for "fixef"

Any suggestions would be greatly appreciated!

R-help at r-project.org mailing list
PLEASE do read the posting guide
and provide commented, minimal, self-contained, reproducible code.

Dit bericht en eventuele bijlagen geven enkel de visie van de schrijver weer 
en binden het INBO onder geen enkel beding, zolang dit bericht niet bevestigd is
door een geldig ondertekend document. The views expressed in  this message 
and any annex are purely those of the writer and may not be regarded as stating 
an official position of INBO, as long as the message is not confirmed by a duly 
signed document.

More information about the R-sig-mixed-models mailing list