R: C-statistic by Begg et al.

BeggC {survAUC} | R Documentation

## C-statistic by Begg et al.

### Description

C-statistic by Begg et al.

### Usage

    BeggC(Surv.rsp, Surv.rsp.new, lp, lpnew)

### Arguments

`Surv.rsp` | A `Surv(.,.)` object containing to the outcome of the training data.
`Surv.rsp.new` | A `Surv(.,.)` object containing the outcome of the test data.
`lp` | The vector of predictors estimated from the training data.
`lpnew` | The vector of predictors obtained from the test data.

### Details

This function implements the C-statistic proposed by Begg et al. (2000). It has the same interpretation as Harrell's C for survival data (implemented in the `rcorr.cens` function of the Hmisc package). `BeggC` is restricted to Cox regression. Specifically, it is assumed that `lp` and `lpnew` are the predictors of a Cox proportional hazards model. Estimates obtained from `BeggC` are valid as long as the Cox model is specified correctly.

### Value

The estimated C-statistic.

### References

Begg, B. C., L. D. Craemer, E. S. Venkatraman and J. Rosai (2000).
Comparing tumor staging and grading systems: a case study and a review of the issues, using thymoma as a model.
Statistics in Medicine 19, 1997–2014.

### See Also

`UnoC`, `GHCI`, `AUC.sh`, `IntAUC`

### Examples

    TR <- ovarian[1:16,]
    TE <- ovarian[17:26,]
    train.fit  <- coxph(Surv(futime, fustat) ~ age,
                        x=TRUE, y=TRUE, method="breslow", data=TR)

    lp <- predict(train.fit)
    lpnew <- predict(train.fit, newdata=TE)
    Surv.rsp <- Surv(TR$futime, TR$fustat)
    Surv.rsp.new <- Surv(TE$futime, TE$fustat)

    Cstat <- BeggC(Surv.rsp, Surv.rsp.new, lp, lpnew)
    Cstat

[Package survAUC version 1.0-5 Index]