Randomly allocate patients to treatment arms — simulate

This function assigns each patient to a treatment arm (e.g., control or treatment) according to specified allocation ratios.

Usage

simulate_allocation(
  data,
  arm_names = c("Control", "Treatment"),
  ratio = c(1, 1)
)

Arguments

data: A data frame of patients (e.g., output of simulate_patients).
arm_names: Character vector of arm names. Default is c("Control","Treatment") for a two-arm trial.
ratio: Numeric vector of allocation ratios for each arm (same length as arm_names). Default is c(1,1) for equal allocation.

Value

The input data frame with an added factor column Arm indicating the treatment group for each patient.

Details

Allocation is done by simple random sampling. The ratio vector is normalized to probabilities. If an arm receives no patients by chance (especially when sample size is small), the Arm factor will still include that level (to preserve all arm levels).

Examples

df <- simulate_patients(10)
# Allocate patients equally to "Placebo" vs "Drug" arms
df <- simulate_allocation(df, arm_names = c("Placebo","Drug"), ratio = c(1,1))
table(df$Arm)
#> 
#> Placebo    Drug 
#>       6       4