?? Dear list:
?? Sometimes I have had "false convergence" problems while performing some analyses with lmer. Usually, I was told that the problem could be an overparameterization. But this time, I've got the false convergence message just at the end of a stepwise model simplification, after removing the last remaining term. Obviously, I would like to know the reason for this, and I would appreciate any ideas about it. I attach the data set I am using. The analysis was performed after standardizing the continuous independent variables (tlength, brithr, briventral, inslarge and cond).?
?? This is the step where I get the error message:
?? s.clutchmodel1.57<-update(s.clutchmodel1.56,~.-brithrst)
Mensajes de aviso perdidos
In mer_finalize(ans) : singular convergence (7)
summary(s.clutchmodel1.57)
Generalized linear mixed model fit by the Laplace approximation
Formula: clsize1 ~ (1 | site/pair) + (1 | year)
?AIC?? BIC logLik deviance
? 30 39.68??? -11?????? 22
Random effects:
?Groups??? Name??????? Variance Std.Dev.
?pair:site (Intercept)? 0??????? 0?????
?site????? (Intercept)? 0??????? 0?????
?year????? (Intercept)? 0??????? 0?????
Number of obs: 83, groups: pair:site, 37; site, 12; year, 2
Fixed effects:
??????????? Estimate Std. Error z value Pr(>|z|)???
(Intercept)? 1.60702??? 0.04915??? 32.7?? <2e-16 ***
---
Signif. codes:? 0 ?***? 0.001 ?**? 0.01 ?*? 0.05 ?.? 0.1 ? ? 1
summary(s.clutchmodel1.56)
Generalized linear mixed model fit by the Laplace approximation
Formula: clsize1 ~ brithrst + (1 | site/pair) + (1 | year)
?? AIC?? BIC logLik deviance
?31.52 43.62 -10.76??? 21.52
Random effects:
?Groups??? Name??????? Variance?? Std.Dev.?
?pair:site (Intercept) 0.0000e+00 0.0000e+00
?site????? (Intercept) 7.6128e-17 8.7251e-09
?year????? (Intercept) 1.0638e-14 1.0314e-07
Number of obs: 83, groups: pair:site, 37; site, 12; year, 2
Fixed effects:
??????????? Estimate Std. Error z value Pr(>|z|)???
(Intercept)? 1.60645??? 0.04918?? 32.67?? <2e-16 ***
brithrst???? 0.03418??? 0.04930??? 0.69??? 0.488???
---
Signif. codes:? 0 ?***? 0.001 ?**? 0.01 ?*? 0.05 ?.? 0.1 ? ? 1
Correlation of Fixed Effects:
???????? (Intr)
brithrst -0.034
?? Do you think the problem could be in the fact that I am including random factors which can explain none of the variance? Should I do the analysis again without including those factors?
?? Thank you very much.
?? Iker
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