Subgroup Search for Treatment Effect Heterogeneity (Improved, Parallelized)

Searches for subgroups with treatment effect heterogeneity using combinations of candidate factors. Evaluates subgroups for minimum prevalence, event counts, and hazard ratio threshold. Parallelizes the main search loop.

Usage

subgroup.search(
  Y,
  Event,
  Treat,
  ID = NULL,
  Z,
  n.min = 30,
  d0.min = 15,
  d1.min = 15,
  hr.threshold = 1,
  max.minutes = 30,
  minp = 0.05,
  rmin = 5,
  details = FALSE,
  maxk = 2,
  parallel_workers = parallel::detectCores()
)

Arguments

Y

Numeric vector of outcome (e.g., time-to-event).

Event

Numeric vector of event indicators (0/1).

Treat

Numeric vector of treatment group indicators (0/1).

ID

Optional vector of subject IDs.

Z

Matrix or data frame of candidate subgroup factors (binary indicators).

n.min

Integer. Minimum subgroup size.

d0.min

Integer. Minimum number of events in control.

d1.min

Integer. Minimum number of events in treatment.

hr.threshold

Numeric. Hazard ratio threshold for subgroup selection.

max.minutes

Numeric. Maximum minutes for search.

minp

Numeric. Minimum prevalence rate for each factor.

rmin

Integer. Minimum required reduction in sample size when adding a factor.

details

Logical. Print details during execution.

maxk

Integer. Maximum number of factors in a subgroup.

parallel_workers

Integer. Number of parallel workers (default: all available cores).

Value

List with found subgroups, maximum HR, search time, configuration info, and filtering statistics.