Est.Cval {survC1}

Esimtation of C

Description

Performs a point estimation of C

Usage

Est.Cval(mydata, tau, nofit=FALSE)

Arguments

mydata

Input data. The 1st column should be time-to-event, and the 2nd column is event indicator (1=event, 0=censor). The rest of the columns are covariates/predictors used in the model. No character variable or missing is allowed.

tau

Truncation time. The resulting C tells how well the given prediction model works in predicting events that occur in the time range from 0 to tau. Note that the survival function for the underlying censoring time distribution needs to be positive at tau.

nofit

If TRUE, the 3rd column of mydata is used as the risk score directly in calculation of C. The default is FALSE.

Value

Dhat

Estimate of C

beta

Estimates for regression coefficient in the Cox model

beta.var

Variance-Covariance matrix for beta above

rs

Risk score of each individial

ft

coxph object with the fitted model

Examples

D=CompCase(pbc[1:200,c(2:4,10:14)]) 
D[,2]=as.numeric(D[,2]==2)
tau=365.25*8
model=D[,c(1,2,4,5)]

Est.Cval(model, tau)$Dhat