lrtest: Log-Rank Test of Survival Curve Difference

In trtswitch: Treatment Switching

Log-Rank Test of Survival Curve Difference

Description

Obtains the log-rank test using the Fleming-Harrington family of weights.

Usage

lrtest(
  data,
  stratum = "",
  treat = "treat",
  time = "time",
  time2 = "",
  event = "event",
  weight = "",
  weight_readj = FALSE,
  rho1 = 0,
  rho2 = 0
)

Arguments

data	The input data frame or list of data frames that contains the following variables: stratum: The stratum. treat: The treatment. time: The follow-up time for right censored data, or the left end of each interval for counting process data. time2: The right end of each interval for counting process data. Intervals are assumed to be open on the left and closed on the right, and event indicates whether an event occurred at the right end of each interval. event: The event indicator, 1=event, 0=no event. weight: The weight for each observation.
stratum	The name(s) of the stratum variable(s) in the input data.
treat	The name of the treatment variable in the input data.
time	The name of the time variable or the left end of each interval for counting process data in the input data.
time2	The name of the right end of each interval for counting process data in the input data.
event	The name of the event variable in the input data.
weight	The name of the weight variable in the input data.
weight_readj	Whether the weight variable at each event time will be readjusted to be proportional to the number at risk by treatment group. Defaults to FALSE.
rho1	The first parameter of the Fleming-Harrington family of weighted log-rank test. Defaults to 0 for conventional log-rank test.
rho2	The second parameter of the Fleming-Harrington family of weighted log-rank test. Defaults to 0 for conventional log-rank test.

Value

A data frame with the following variables:

• uscore: The numerator of the log-rank test statistic.

• vscore: The variance of the log-rank score test statistic.

• logRankZ: The Z-statistic value.

• logRankPValue: The two-sided p-value.

• weight_readj: Whether the weight variable will be readjusted.

• rho1: The first parameter of the Fleming-Harrington weights.

• rho2: The second parameter of the Fleming-Harrington weights.

Author(s)

Kaifeng Lu, [e-mail]

Examples

lrtest(rawdata[rawdata$iterationNumber == 1, ], 
       stratum = "stratum", treat = "treatmentGroup", 
       time = "timeUnderObservation", event = "event", 
       rho1 = 0.5, rho2 = 0)
             

trtswitch documentation built on Jan. 10, 2026, 5:08 p.m.