[R] Why warnings using lmer-model with family=binomial
asa.granberg at emg.umu.se
Wed Apr 11 15:30:24 CEST 2007
My question is why, and what I can do about that
I sometimes, but not always, get warning-messages like
nlminb returned message singular convergence (7)
in: LMEopt(x = mer, value = cv)
IRLS iterations for PQL did not converge
when trying to fit a model looking like this:
family="binomial") to four similar data sets?
All four data sets consists of four columns;
Fungus (1 or 2), Family (1-30), Diseased and Healthy.
Fungus Family Diseased Healthy
1 1 3 7
2 1 1 5
1 2 2 16
2 2 2 14
...and so on up to totally 30 families.
One of the data sets works perfectly fine and
gives no warnings, but for the others i get
different amount of warning messages. Between the
data sets it is only the number of diseased anf
healthy for each family and fungus that differ.
Does anyone have any idea why this happens and
how I can get around it (I'm mainly interested in the interaction term...)?
Grateful for any help
Åsa Granberg, Doktorand / Phd-student
Ekologi, miljö och geovetenskap
901 87 Umeå
Department of Ecology and Environmental Science
901 87 Umeå, Sweden
Phone: +46 (0)90 786 7461
Fax: +46 (0)90 786 6705
e-mail:asa.granberg at emg.umu.se
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