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Weighted Log-Rank and Difference Estimate at a Specified Time

Source: R/km_wlr_calculations_helpers.R
wlr_dhat_estimates.Rd

Computes the weighted log-rank statistic, its variance, the difference in survival at a specified time (tzero), the variance of the difference, their covariance, and correlation, using flexible time-dependent weights. The weighting scheme is selected via the scheme argument and is calculated using wt.rg.S.

Usage

wlr_dhat_estimates(
  dfcounting,
  scheme = "fh",
  scheme_params = list(rho = 0, gamma = 0),
  tzero = NULL
)

Arguments

dfcounting

List output from df_counting containing risk sets, event counts, and survival estimates.

scheme

Character string specifying weighting scheme. One of: "fh" (Fleming-Harrington), "schemper", "XO", "MB", "custom_time", or "custom_code".

scheme_params

Named list with numeric weighting parameters rho and gamma (used for "fh" and "custom_code" schemes).

tzero

Time point at which to evaluate the difference in survival (default: 24).

Value

A list with elements:

lr

Weighted log-rank test statistic.

sig2_lr

Variance of the log-rank statistic.

dhat

Difference in survival at tzero.

cov_wlr_dhat

Covariance between log-rank and difference at tzero.

sig2_dhat

Variance of the difference at tzero.

cor_wlr_dhat

Correlation between log-rank and difference at tzero.

Details

The weighting scheme is selected via the scheme argument and calculated using wt.rg.S. Supports standard Fleming-Harrington, Schemper, XO (Xu & O'Quigley), MB (Maggir-Burman), custom time-based, and custom code weights.