Displaying 3 results from an estimated 3 matches for "pdcheck".
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podcheck
2008 Mar 05
1
coxme - fitting random treatment effect nested within centre
...(3,3),dimnames=list(ugroup,ugroup))
> mat2=bdsmatrix(rep(c(0,0,0,0,0,0,0,0,1),3),blocksize=rep(3,3),dimnames=list(ugroup,ugroup))
> group=paste(dat1$centre,dat1$treat,sep='/')
> coxme(Surv(time,status) ~ as.factor(treat), data=dat1,random= ~1|group,varlist=list(mat1,mat2),rescale=F,pdcheck=FALSE)
Error in coxme.fit(X, Y, strats, offset, init, control, weights = weights, :
Random effects variance is not spd
Could anyone help me correcting this error?
Many thanks in advance.
Ruwanthi
____________________________________________________________________________________
Looki...
2012 Oct 07
1
variances of random effects in coxme
...Cox
models with complex random effects. Unfortunately, I sometimes get
surprising estimations of the variances of the random effects.
I ran models with different fixed covariates but always with the same 3
random effects defined by the argument
varlist=coxmeMlist(list(mat1,mat2,mat3), rescale = F, pdcheck = F,
positive=F). I get a few times exactly the same estimations of the
parameters of the random effects whereas the fixed effects of the models
are different:
Random effects
Group Variable Std Dev Variance
idp Vmat.1 0.10000000 0.01000000
Vmat.2 0.02236068 0.00050000
Vmat...
2008 Dec 28
1
Random coefficients model with a covariate: coxme function
...), dimnames=list(ugroup, ugroup))
mat2<-bdsmatrix(rep(c(0,0,0,1), 32),
blocksize=rep(2,32), dimnames=list(ugroup, ugroup))
group1<-paste(data1$centers, data1$treat, sep="/")
fit2<- coxme(Surv(y, uncens)~ treat + covar,
data1,random=~1|group1, varlist=list(mat1, mat2),rescale=F, pdcheck=F)
However, I'm not sure about how to proceed to
introduce the random slope for covar. Should I
introduce a third variance matrix per center and
redefine the groups as follows?
ugroup<-paste(rep(1:32, each=3), rep(c(0:1,"z"), 32), sep='/') #unique groups
mat1_1<-bds...