logpl {survcomp} | R Documentation

## Function to compute the log partial likelihood of a Cox model

### Description

The function computes the log partial likelihood of a set of coefficients given some survival data.

### Usage

    logpl(pred, surv.time, surv.event, strata, na.rm = FALSE, verbose = FALSE)

### Arguments

`surv.time` | vector of times to event occurrence
`surv.event` | vector of indicators for event occurrence
`pred` | linear predictors computed using the Cox model
`strata` | stratification variable
`na.rm` | `TRUE` if the missing values should be removed from the data, `FALSE` otherwise
`verbose` | verbosity of the function

### Value

vector of two elements: `logpl` and `event` for the estimation of the log partial likelihood and the number of events, respectively

### Author(s)

Benjamin Haibe-Kains

### References

Cox, D. R. (1972) "Regression Models and Life Tables", Journal of the Royal Statistical Society Series B, 34, pages 187–220.

### See Also

`coxph`, `cvpl`

### Examples

    set.seed(12345)
    age <- rnorm(100, 50, 10)
    stime <- rexp(100)
    cens <- runif(100,.5,2)
    sevent <- as.numeric(stime <= cens)
    stime <- pmin(stime, cens)
    dd <- data.frame("stime"=stime, "sevent"=sevent, "age"=age)
    ##Cox model
    coxm <- coxph(Surv(stime, sevent) ~ age, data=dd)
    ##log partial likelihood of the null model
    logpl(pred=rep(0, nrow(dd)), surv.time=stime, surv.event=sevent)
    ##log partial likelihood of the Cox model
    logpl(pred=predict(object=coxm, newdata=dd), surv.time=stime, surv.event=sevent)
    ##equivalent to
    coxm$loglik

[Package survcomp version 1.40.0 Index]