survreg {survival} | R Documentation

## Regression for a Parametric Survival Model

### Description

Regression for a parametric survival model. These are all time-transformed location models, with the most useful case being the accelerated failure models that use a log transformation.

### Usage

    survreg(formula=formula(data), data=parent.frame(), weights,
    subset,na.action,dist="weibull",  init=NULL, scale=0,
     control=survreg.control(),parms=NULL,model=FALSE, x=FALSE,
     y=TRUE, robust=FALSE, ...)

### Arguments

`formula` | a formula expression as for other regression models. See the documentation for `lm` and `formula` for details.
`data` | optional data frame in which to interpret the variables occurring in the formula.
`weights` | Optional observation weights
`subset` | subset of the observations to be used in the fit.
`na.action` | function to be used to handle any NAs in the data.
`dist` | assumed distribution for y variable. If the argument is a character string, then it is assumed to name an element from `survreg.distributions`. These include `"weibull"`, `"exponential"`, `"gaussian"`, `"logistic"`, `"lognormal"` and `"loglogistic"`. Otherwise, it is assumed to be a user defined list conforming to the format described in `survreg.distributions`.
`parms` | a list of fixed parameters. For the t-distribution for instance this is the degrees of freedom; most of the distributions have no parameters.
`init` | optional vector of initial values for the parameters.
`scale` | optional fixed value for the scale. If set to <=0 then the scale is estimated.
`control` | a list of control values, in the format producted by `survreg.control`.
`model` | if TRUE, the model frame is returned.
`x` | if TRUE, then the X matrix is returned.
`y` | if TRUE, then the y vector (or survival times) is returned.
`robust` | if TRUE, sandwich standard errors are computed. Defaults to TRUE when `formula` contains a `cluster` term.
`...` | other arguments which will be passed to `survreg.control`.

### Value

an object of class `survreg` is returned.

### Compatibility note

This routine underwent significant changes from survival4 to survival5. The survreg.old function gives a backwards-compatible interface. In S-PLUS the new function is called `survReg` and the old one `survreg`.

### See Also

`survreg.object`, `survreg.distributions`, `pspline`, `frailty`, `ridge`, `survreg.old`

### Examples

    ## These are all the same
    survreg(Surv(futime, fustat) ~ ecog.ps + rx, ovarian, dist='weibull',scale=1)
    survreg(Surv(futime, fustat) ~ ecog.ps + rx, ovarian,
    dist="exponential")
    survreg.old(Surv(futime, fustat) ~ ecog.ps + rx, ovarian, dist='extreme',fixed=list(scale=1),link="log")

[Package survival version 2.31 Index]