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Simulate Trial Data from a GLM Data Generating Mechanism

Source: R/simulate_from_glm_dgm.R
simulate_from_glm_dgm.Rd

Generates a simulated clinical trial dataset by sampling from the super-population in a "glm_dgm" object. Assigns treatment and generates outcomes from the individual-level potential outcomes stored in the DGM.

Usage

simulate_from_glm_dgm(
  dgm,
  n = NULL,
  rand_ratio = 1,
  seed = NULL,
  draw_treatment = TRUE,
  replace = TRUE,
  baseline = c("resample", "fixed")
)

Arguments

dgm

An object of class "glm_dgm" created by generate_glm_dgm.

n

Integer. Sample size. If NULL (default), uses the entire super-population without resampling.

rand_ratio

Numeric. Treatment:control randomisation ratio. Default 1 (1:1 allocation).

seed

Integer. Random seed. Default NULL (no explicit seed; use the calling environment's RNG state).

draw_treatment

Logical. If TRUE (default), randomly assigns treatment. If FALSE, retains the treatment column from the super-population.

replace

Logical sampling scheme for drawing the n subjects from dgm$df_super. TRUE (default) samples with replacement (bootstrap-style trial sampling). FALSE samples without replacement and so requires n <= nrow(dgm$df_super); treatment is still re-randomised and the outcome re-drawn. Used to draw the full pool once (n = nrow(dgm$df_super), replace = FALSE) for the beta(Hhat) evaluation frame. Ignored on the n = NULL path.

baseline

\"resample\" (default; draw the trial panel from the super-population) or \"fixed\" (use dgm$df_source – the observed panel, every patient exactly once, observed order; requires a DGM built by a version that stores df_source; n must be NULL or nrow(df_source)).

Value

A data frame with columns:

id

Integer subject identifier.

y_sim

Simulated outcome.

treat_sim

Treatment indicator (0/1).

flag_harm

True subgroup membership indicator.

Plus all covariate columns from the super-population.

For binary outcomes, y_sim is a 0/1 Bernoulli draw from the potential outcome probabilities (p0 or p1). There is no event_sim column – for ForestSearch, set event.name = "y_sim".

See also

generate_glm_dgm, run_simulation_analysis

Examples

if (FALSE) { # \dontrun{
dgm <- generate_glm_dgm(...)
df  <- simulate_from_glm_dgm(dgm, n = 500, seed = 42)
table(df$y_sim, df$treat_sim)
} # }