[R-sig-ME] ICC from lmer with back transform

[fabien leboeuf]

Hello
what a nice idea to have a forum dedidated to lmer question :-). i came
acros it from cross-validated.

Here is my question:

I want to calculate the ICC from a mixed model coded with lmer as follow.

model <- lmer(formula = log(VARIABLE) ~ 1
+(1|Side)+(1|Asessor)+(1|ID), data = data,REML=FALSE)

am i wrong if i compute the iCC from back transform , like that

vc <- as.data.frame((VarCorr(model)))
ICC_log = sum(exp(vc$vcov[1]),exp(vc$vcov[3]))/(sum(exp(vc$vcov)))

I appreciate any replies.

Fabien

-- 
Fabien

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Fabien Leboeuf
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Ingénieur "analyste du mouvement" du Pole 10, CHU Nantes, France
Chercheur associé de l'Université de Salford, Manchester, Royaume uni
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Laboratoire d'analyse du mouvement
85 rue saint Jacques
44093 Nantes, FRANCE
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