coxsurv.fit {survival} | R Documentation |

## A direct interface to the ‘computational engine’ of survfit.coxph

### Description

This program is mainly supplied to allow other packages to invoke the survfit.coxph function at a ‘data’ level rather than a ‘user’ level. It does no checks on the input data that is provided, which can lead to unexpected errors if that data is wrong.

### Usage

```
coxsurv.fit(ctype, stype, se.fit, varmat, cluster,
y, x, wt, risk, position, strata, oldid,
y2, x2, risk2, strata2, id2, unlist=TRUE)
```

### Arguments

`stype` |
survival curve computation: 1=direct, 2=exp(-cumulative hazard) |

`ctype` |
cumulative hazard computation: 1=Breslow, 2=Efron |

`se.fit` |
if TRUE, compute standard errors |

`varmat` |
the variance matrix of the coefficients |

`cluster` |
vector to control robust variance |

`y` |
the response variable used in the Cox model. (Missing values removed of course.) |

`x` |
covariate matrix used in the Cox model |

`wt` |
weight vector for the Cox model. If the model was unweighted use a vector of 1s. |

`risk` |
the risk score exp(X beta + offset) from the fitted Cox model. |

`position` |
optional argument controlling what is counted as 'censored'. Due to time dependent covariates, for instance, a subject might have start, stop times of (1,5)(5,30)(30,100). Times 5 and 30 are not 'real' censorings. Position is 1 for a real start, 2 for an actual end, 3 for both, 0 for neither. |

`strata` |
strata variable used in the Cox model. This will be a factor. |

`oldid` |
identifier for subjects with multiple rows in the original data. |

`y2` , `x2` , `risk2` , `strata2` |
variables for the hypothetical subjects, for which prediction is desired |

`id2` |
optional; if present and not NULL this should be
a vector of identifiers of length |

`unlist` |
if |

### Value

a list containing nearly all the components of a `survfit`

object. All that is missing is to add the confidence intervals, the
type of the original model's response (as in a coxph object), and the
class.

### Note

The source code for for both this function and
`survfit.coxph`

is written using noweb. For complete
documentation see the `inst/sourcecode.pdf`

file.

### Author(s)

Terry Therneau

### See Also

*survival*version 3.7-0 Index]