# Confidence bands for a survival curve

### Description

A function for constructing confidence bands for a survival curve. This is in contrast to pointwise confidence intervals for the survival curve.

### Usage

1 2 3 |

### Arguments

`x` |
An object of class |

`confType` |
The type of confidence ban. There are three options: |

`confLevel` |
Confidence level. Only numerical values of |

`type` |
The type of method used to construct the confidence band. Available options are EP ( |

`tL` |
A minimum time to be considered. The default is the first observed or censored time. |

`tU` |
A maximum time to be considered. The default it the last observed time. |

### Details

See References.

### Value

Returns an object of class `"confBands"`

, which is a list of three items:

`time` |
A vector of times. |

`lower` |
A vector of the lower band values corresponding to the times. |

`upper` |
A vector of the upper band values corresponding to the times. |

### Author(s)

David M Diez

### References

Klein JP, Moeschberger ML (2003). Survival Analysis: Techniques for Censored and Truncated Data. Springer Verlag, New York.

### See Also

`relapse`

### Examples

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | ```
#=====> 5. Kaplan-Meier confidence bands <=====#
data(bmt)
attach(bmt)
mySurv <- Surv(t2[group==1], d3[group==1])
#pdf("confBand.pdf", 7, 4.5)
#par(mar=c(3.9, 3.9, 2.5, 1), mgp=c(2.6, 0.7, 0))
plot(survfit(mySurv ~ 1), xlim=c(100, 600), xlab='time',
ylab='Estimated Survival Function',
main='Reproducing Confidence Bands, bone marrow transplant')
myCB <- confBands(mySurv)
lines(myCB, lty=3)
legend(100, 0.3, legend=c('K-M survival estimate',
'pointwise intervals','EP confidence bands'), lty=1:3)
#dev.off()
detach(bmt)
``` |