PwrGSD (version 2.3.8)

agghaz: Aggregated Hazard

Description

Computes the MLE for the model that assumes piecewise constant hazards on intervals defined by a grid of points. One applications for example is to calculate monthly hazard rates given numbers of events, numbers at risk and event times reported to the day. Can also handle time to event data stratified on a blocking factor.

Usage

agghaz(t.agg, time, nrisk, nevent)

Value

time.a

User supplied left-hand endpoints of intervals of hazard constancy

nrisk.a

Numbers at risk on specified intervals

nevent.a

Numbers of events on specified intervals

Arguments

t.agg

Vector defining intervals upon which the user wants constant hazard rates.

time

Event times, possibly stratified on a blocking factor into multiple columns, in units that occur in enough numbers per interval specified above. If there is just a single column then it must be in column form (see example below).

nrisk

Numbers at risk at specified event times

nevent

Numbers of events at specified event times

Author

Grant Izmirlian <[e-mail]>

Examples

  library(PwrGSD)
  data(lung)
  fit.msf <- mysurvfit(Surv(time, I(status==2)) ~ sex, data=lung)

  ## A single stratum:
  with(fit.msf$Table, agghaz(30, time, cbind(nrisk.sex1), cbind(nevent.sex1)))

  ## Multiple strata--pooled and group 1:
  with(fit.msf$Table, agghaz(30, time, cbind(nrisk.sex1+nrisk.sex2,nrisk.sex1),
                                       cbind(nevent.sex1+nevent.sex2,nevent.sex1)))