subcluster {frailtypack}

Identify subclusters

Description

This is a special function used in the context of survival nested or joint nested models. It identifies correlated groups of observations within other groups defined by using 'cluster' function from 'survival' package, and is used on the right hand side of 'frailtyPenal' formula for fitting a nested or joint nested model. Using subcluster() in a formula implies that a nested or a joint nested frailty model is estimated.

Usage

subcluster(x)

Arguments

x

A character, factor, or numeric variable which is supposed to indicate the variable subgroup

Value

x

A variable identified as a subcluster

See Also

frailtyPenal

Examples

## Not run: 

data(dataNested)
modClu <- frailtyPenal(Surv(t1,t2,event)~cluster(group)+
subcluster(subgroup)+cov1+cov2,data=dataNested,
n.knots=8,kappa=c(50000,50000),hazard="Splines")

print(modClu)

#-- here is generated cluster (30 clusters)
readmissionNested <- transform(readmission,group=id%%30+1)

modJointNested_Splines <- frailtyPenal(formula = Surv(t.start, t.stop, event)
	~ subcluster(id) + cluster(group) + dukes + 
	terminal(death), formula.terminalEvent = ~dukes, 
	data = readmissionNested, recurrentAG = TRUE, n.knots = 8, 
	kappa = c(9.55e+9, 1.41e+12), initialize = TRUE)


## End(Not run)