Hi,



I am running a negative binomial model using Gamlss and when I try to include random effect, I get the following message:



Warning messages:
1: In vcov.gamlss(object, "all") :
  addive terms exists in the mu formula standard errors for the linear terms maybe are not appropriate
2: In vcov.gamlss(object, "all") :
  addive terms exists in the  sigma  formula standard errors for the linear terms maybe are not appropriate
3: In summary.gamlss(model1) :
  summary: vcov has failed, option qr is used instead

I still get the output for the fixed effects but not for the random effects. Can you recommend on a solution for this problem?



Below is the code that I wrote:



install.packages("gamlss")
library(utils)
library(MASS)
library (gamlss)

Data_Reduced = read.table(file.choose(), header=TRUE, sep="\t")
model1<-gamlss(Events~ factor(Solo_Time) + factor(Fleet)+ Father_SS + Mother_SS + random(factor(Driver_ID)) + offset(logDuration), sigma.fo=~random(factor(Driver_ID)), data = na.omit(Data_Reduced), family=NBI, na.action = "na.omit")
summary(model1)


Thanks in advance.

Best regards,
Haneen


--------------------------------------------------------------------------------------
Haneen Farah, Ph.D.
Department of Transport Sciences
School of Architecture & Build Environment
KTH- Royal Institute of Technology
Teknikringen 72, SE-100 44 Stockholm
Tel: +46-8-7907977
fhanin@kth.se<mailto:fhanin@kth.se>
http://home.abe.kth.se/~fhanin/


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