Estimates the probability of survival past some specified time using landmark estimation for a randomized trial setting
surv.land.rct(tl, dl, tt, landmark, short = NULL, z.cov = NULL, var = FALSE,
conf.int = FALSE, weight.perturb = NULL, perturb.vector = FALSE, bw = NULL)A list is returned:
the estimate of survival at the time of interest, \(\hat{S}(t) = P(T>t)\)
the variance estimate of \(\hat{S}(t)\); if var = TRUE or conf.int = TRUE
a vector of size 2; the 95% confidence interval for \(\hat{S}(t)\) based on a normal approximation; if conf.int = TRUE
a vector of size 2; the 95% confidence interval for \(\hat{S}(t)\) based on sample quantiles of the perturbed values, described above; if conf.int = TRUE
a vector of size x where x is the number of columns of the provided weight.perturb matrix (or x=500 if weight.perturb is not provided); the perturbed values of \(\hat{S}(t)\); if perturb.vector = TRUE and either var=TRUE or conf.int = TRUE
observed event time of primary outcome, equal to min(T, C) where T is the event time and C is the censoring time.
event indicator, equal to I(T<C) where T is the event time and C is the censoring time.
the time of interest, function estimates the probability of survival past this time
the landmark time
a matrix of intermediate event information, there should be two columns for each intermediate event, the first column contains the observed intermediate event time, equal to min(TS, C) where TS is the event time and C is the censoring time, and the second column contains the event indicator, equal to I(TS<C)
matrix of baseline covariate information
TRUE or FALSE; indicates whether a variance estimate for survival is requested, default is FALSE.
TRUE or FALSE; indicates whether a 95% confidence interval for survival is requested, default is FALSE.
a n by x matrix of weights where n = length of tl; used for perturbation-resampling, default is null. If var or conf.int is TRUE and weight.perturb is not provided, the function generates exponential(1) weights.
TRUE or FALSE; indicates whether a vector of the perturbed values of the survival estimate is requested, default is FALSE. This argument is ignored if both var and conf.int are FALSE.
bandwidth used for kernel estimation, default is NULL
Layla Parast
See documentation for delta.land.rct for details.
Parast, L., Tian, L., & Cai, T. (2014). Landmark Estimation of Survival and Treatment Effect in a Randomized Clinical Trial. Journal of the American Statistical Association, 109(505), 384-394.
data(example_rct)
example_rct.treat = example_rct[example_rct$treat == 1,]
#executable but takes time
#surv.land.rct(tl=example_rct.treat$TL, dl = example_rct.treat$DL, tt=2, landmark = 1,
#short = cbind(example_rct.treat$TS,example_rct.treat$DS), z.cov = example_rct.treat$Z)
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