CODEWITHSUNDEEP
lme4
canderson156
canderson156

Reputation: 1281

Why won't VarCorr display variance for lmerModLmerTest or glmerMod objects?

I'm trying to extract this section of the model summary from a set of glmms. I want both the variance and the standard deviation.

Random effects:
 Groups Name        Variance Std.Dev.
 herd   (Intercept) 0.4123   0.6421  
Number of obs: 56, groups:  herd, 15

I tried following this answer Extract random effect variances from lme4 mer model object

But I can't seem to get the variance, only the standard deviation. I thought perhaps this was because I was using glmer instead of lmer, but I seem to get the same results.

gm1 <- lmer( size ~ period + (1 | herd), data = cbpp)

summary(gm1)
Random effects:
 Groups   Name        Variance Std.Dev.
 herd     (Intercept) 44.40    6.664   
 Residual             14.51    3.810   
Number of obs: 56, groups:  herd, 15


> VarCorr(gm1, comp="Variance")
 Groups   Name        Std.Dev.
 herd     (Intercept) 6.6636  
 Residual             3.8096  
> VarCorr(gm1, comp="Std.Dev.")
 Groups   Name        Std.Dev.
 herd     (Intercept) 6.6636  
 Residual             3.8096  
> VarCorr(gm1, comp=c("Variance","Std.Dev."))
 Groups   Name        Std.Dev.
 herd     (Intercept) 6.6636  
 Residual             3.8096  





gm2 <- glmer(cbind(incidence, size - incidence) ~ period + (1 | herd),
             data = cbpp, family = binomial)

summary(gm2)
Random effects:
 Groups Name        Variance Std.Dev.
 herd   (Intercept) 0.4123   0.6421  
Number of obs: 56, groups:  herd, 15


> VarCorr(gm2, comp="Variance")
 Groups Name        Std.Dev.
 herd   (Intercept) 0.64207 
> VarCorr(gm2, comp="Std.Dev.")
 Groups Name        Std.Dev.
 herd   (Intercept) 0.64207 
> VarCorr(gm2, comp=c("Variance","Std.Dev."))
 Groups Name        Std.Dev.
 herd   (Intercept) 0.64207

Any ideas what might be going on here?

Upvotes: 2

Views: 509

Answers (1)

Ben Bolker
Ben Bolker

Reputation: 226087

comp is an argument to the print() method, not to VarCorr.

print(VarCorr(gm1), comp=c("Variance", "Std.Dev."))
 Groups   Name        Variance Std.Dev.
 herd     (Intercept) 44.404   6.6636  
 Residual             14.513   3.8096

You might also be interested in

as.data.frame(VarCorr(gm1))[,c("vcov", "sdcor")]
      vcov    sdcor
1 44.40371 6.663611
2 14.51309 3.809605

Upvotes: 2

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