That is certainly possible, though it is a noddy dataset and the problem persists with the full dataset if the Sex * Ethnicity terms are omitted.

Thanks for your thoughts,
Tim Cole
---
Tim.Cole@ucl.ac.uk<mailto:Tim.Cole@ucl.ac.uk> Phone +44(0)20 7905 2666 Fax +44(0)20 7905 2381
Centre for Paediatric Epidemiology and Biostatistics
UCL Institute of Child Health, London WC1N 1EH, UK

From: David Duffy <David.Duffy@qimr.edu.au<mailto:David.Duffy@qimr.edu.au>>
Date: Wednesday, 8 January 2014 00:04
To: Tim Cole <tim.cole@ucl.ac.uk<mailto:tim.cole@ucl.ac.uk>>
Cc: "r-sig-mixed-models@r-project.org<mailto:r-sig-mixed-models@r-project.org>" <r-sig-mixed-models@r-project.org<mailto:r-sig-mixed-models@r-project.org>>
Subject: Re: [R-sig-ME] R-sig-mixed-models Digest, Vol 85, Issue 6

On Wed, 8 Jan 2014, Cole, Tim wrote:

The offending code is
mod <- glmer(mat ~ log(DecAge) + Sex * Ethnicity + (1 | BHID), family=binomial, nAGQ=0, data=df)

The error message is simple to generate with a
trivial dataset, restricted to subjects with 2 to 4 records and both 0
and 1 values for mat.

mat is a binary mature bone measure, which for each subject consists of
zero or more 0s followed by zero or more 1s, the 0/1 transition
providing useful information about the age of maturity.

In your example, it looks like quasi-separation for mat v. DecAge in males
might be to blame (when I plot them), and:

library(glmmML)
glmmML(mat ~ log(DecAge) + Sex * Ethnicity, cluster=BHID, data=df,
        control = list(maxit = 2000))
[glmmml] fail = 1
Max. No. of iterations reached without convergence

Cheers, David Duffy.

| David Duffy (MBBS PhD)
| email: David.Duffy@qimrberghofer.edu.au<mailto:David.Duffy@qimrberghofer.edu.au>  ph: INT+61+7+3362-0217 fax: -0101
| Genetic Epidemiology, QIMR Berghofer Institute of Medical Research
| 300 Herston Rd, Brisbane, Queensland 4006, Australia  GPG 4D0B994A



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