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Sample Kaplan-Meier Empirical Points for Hazard Plot Overlay

Source: R/hazard-plot.R
sample_hazard_empirical.Rd

Simulates patient-level survival data from a Weibull distribution and returns Kaplan-Meier estimates at a small number of binned time points, matching the structure of the SAS plout dataset used as an empirical overlay in tp.hp.dead.sas and related templates.

Usage

sample_hazard_empirical(
  n = 500,
  time_max = 10,
  n_bins = 6,
  groups = NULL,
  shape = 1.5,
  scale = 8,
  ci_level = 0.95,
  seed = 42L
)

Arguments

n

Number of simulated patients. Default 500.

time_max

Upper end of the follow-up window (years). Default 10.

n_bins

Number of time points at which KM is evaluated. Analogous to the discrete annotation points in the SAS templates. Default 6.

groups

NULL for a single group, or a named numeric vector of hazard multipliers matching those passed to sample_hazard_data().

shape

Weibull shape parameter. Default 1.5.

scale

Weibull scale parameter (years). Default 8.0.

ci_level

Confidence level. Default 0.95.

seed

Random seed. Default 42.

Value

A data frame with columns time, estimate, lower, upper, and (when groups is not NULL) group.

Details

SAS column mapping:

  • time ← IV_DEAD / iv_dead (evaluation time points)

  • estimate ← CUM_SURV (KM survival estimate, 0–100 %)

  • lower ← CL_LOWER (lower 95 % CI)

  • upper ← CL_UPPER (upper 95 % CI)

  • group ← stratification variable (when groups is not NULL)

See also

hv_hazard(), sample_hazard_data()

Examples

emp <- sample_hazard_empirical(n = 500, time_max = 10, n_bins = 6)
head(emp)
#>        time estimate    lower    upper
#> 1  1.666667 90.00000 87.02011 92.32601
#> 2  3.333333 76.77536 72.74817 80.28954
#> 3  5.000000 63.03903 58.37830 67.32977
#> 4  6.666667 48.42234 43.43337 53.22442
#> 5  8.333333 36.81403 31.76328 41.86537
#> 6 10.000000 26.80533 21.84393 32.00013

emp2 <- sample_hazard_empirical(
  n = 400, time_max = 10,
  groups = c("No Takedown" = 1.0, "Takedown" = 0.65)
)
head(emp2)
#>        time estimate    lower    upper       group
#> 1  1.666667 91.25000 88.02522 93.63770 No Takedown
#> 2  3.333333 75.64891 71.09026 79.59367 No Takedown
#> 3  5.000000 62.09290 56.86556 66.87818 No Takedown
#> 4  6.666667 48.38904 42.87023 53.68082 No Takedown
#> 5  8.333333 32.07913 26.70311 37.56790 No Takedown
#> 6 10.000000 24.43818 19.19470 30.03370 No Takedown