Generalized Two-Sample Kolmogorov-Smirnov Test for Right-Censored Data

This function can perform the generalized two-sample Kolmogorov-Smirnov test for right-censored data that proposed by Fleming et al. (1980).

Usage

gstest(formula, data)

Arguments

formula: a formula object, which must have a Surv object as the response on the left of the ~ operator and only one term on the right. This test is a two-sample test, and this function only supports a two-level covariate. This function treats 1 as an event and 0 as a censoring.
data: a data frame in which to interpret the variables named in the formula.

Value

A: Test statistic \(A\); see Fleming et al. (1980).
R: Test statistic \(R\); see Fleming et al. (1980).
pval: Two-sieded P-value.

References

Fleming, D., O'Fallon, JR., O'Brien, P.C., and Harrington, DP. (1980). Modified Kolmogorov-Smirnov test procedures with application to arbitrarily right-censored data. Biometrics 36(4): 607-625. https://doi.org/10.2307/2556114

Examples

library(survival)

# Example 1 of Fleming et al. (1980)
df1 <- data.frame(
  y = c(28,89,175,195,309,377,393,421,447,462,709,744,770,1106,1206,
        34,88,137,199,280,291,299,300,309,351,358,369,369,370,375,
        382,392,429,451,1119),
  event = c(1,1,1,1,1,0,0,0,0,1,0,0,0,0,0,
            1,1,1,1,1,1,0,0,1,1,1,1,1,1,1,1,1,0,1,0),
  arm = c(0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
          1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)
)
# A = 1.834, R = 0.653, Two-sided P = 0.00223
gstest(Surv(y, event) ~ arm, df1)
#>          A         R        pval
#> 1 1.834024 0.6529769 0.002226671