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2025-01-12 00:52:51 +08:00
#
# Formal test of the quantile routine for survfit
library(survival)
aeq <- function(x, y, ...) all.equal(as.vector(x), as.vector(y), ...)
# There are 8 cases: strata Y/N, ncol(surv) >1, conf.int = T/F
# Subcase: the quantile exactly agrees with a horizontal segment of
# the curve or not.
# First do the 4 cases where fit$surv is a vector
#
test1 <- data.frame(time= c(9, 3,1,1,6,6,8, 10),
status=c(1,NA,1,0,1,1,0, 0),
x= c(0, 2,1,1,1,0,0, 0))
# True survival = (6/7) * (3/5) * (1/2) for overall
# The q's are chosen to include a point < first jump, mid, after last jump,
# and exact intersections with the "flats" of the curve.
#
qq <- c(13/14, 6/7, 2/3, .5, 9/35, .1)
# Nothing on the right hand side, simple survival (no strata)
fit1 <- survfit(Surv(time, status) ~ 1, test1, conf.type='none')
aeq(quantile(fit1, 1-qq), c(1, 3.5, 6, 9, 9.5, NA)) #without conf.int
fit2 <- survfit(Surv(time, status) ~ 1, test1) #with conf.int
aeq(quantile(fit2, 1-qq),
list(quantile = c(1, 3.5, 6, 9, 9.5, NA),
lower = c(1,1,1,6,6,9),
upper = rep(as.numeric(NA), 6)), check.attributes=FALSE)
aeq(quantile(fit2, 1-qq, FALSE), c(1, 3.5, 6, 9, 9.5, NA))
# Now a variable on the right (strata in the result)
# curve 0: (t=6, S=3/4), (t=9, S=3/8)
# curve 1: (t=1, S=2/3), (t=6, S= 0)
fit1 <- survfit(Surv(time, status) ~ x, test1, conf.type='none')
aeq(quantile(fit1, 1-qq),
matrix(c(6,6,9,9,NA,NA, 1,1,3.5, 6,6,6), nrow=2, byrow=T))
fit2 <- survfit(Surv(time, status) ~ x, test1)
aeq(quantile(fit2, 1-qq, FALSE),
matrix(c(6,6,9,9,NA,NA, 1,1,3.5, 6,6,6), nrow=2, byrow=T))
temp <- quantile(fit2, 1-qq)
aeq(temp$quantile, matrix(c(6,6,9,9,NA,NA, 1,1,3.5, 6,6,6), nrow=2, byrow=T))
aeq(temp$lower, matrix(c(6,6,6,6,9,9, 1,1,1,1, NA,NA), nrow=2, byrow=T))
aeq(temp$upper, rep(as.numeric(NA), 12))
# Second major case set -- a survfit object where fit$surv is a matrix
# This arises from coxph models
# There is only 1 subject with ph.ecog=3 which is a nice edge case
cfit <- coxph(Surv(time, status) ~ age + strata(ph.ecog), lung)
sfit <- survfit(cfit, newdata=data.frame(age=c(50, 70)))
qtot <- quantile(sfit, qq)
for (i in 1:4) {
for (j in 1:2) {
temp <- quantile(sfit[i,j], qq)
print(c(aeq(qtot$quantile[i,j,], temp$quantile),
aeq(qtot$upper[i,j,], temp$upper),
aeq(qtot$lower[i,j,], temp$lower)))
}
}
temp <- quantile(sfit, qq, conf.int=FALSE)
all.equal(qtot$quantile, temp)