On 09/14/2012 05:00 AM, r-help-request at r-project.org wrote:
Hello, Why the correlation between the random effects is negative? library(coxme) rats1<- coxme(Surv(time, status) ~ (1|litter), rats) random.effects(rats1)[[1]] #one value for each of the 50 litters print(rats1) rats2<- lmekin(time ~ (1|litter), rats) fixed.effects(rats2) random.effects(rats2)[[1]] #one value for each of the 50 litters print(rats2) cor(random.effects(rats1)[[1]],random.effects(rats2)[[1]]) Thanks
Because coxph models the death rate, so large coefficients indicate bad news, and lme is modeling the surival time where large coefficients are good news. Terry T