Plot predictive-probability decision maps

Draws one decision map per interim look across simulated trials. The horizontal axis is the predictive probability of success if enrollment continues to the maximum sample size, and the vertical axis is the predictive probability of success if enrollment stops at the current sample size. Shaded regions and dashed lines show the futility, continuation, stopping-accrual-for-expected-success, and immediate-success rules. Identical points are aggregated; point size indicates their frequency.

Usage

plot_sim_decisions(x)

Arguments

x

A required result returned by sim_trials() with return_trace = TRUE, or the corresponding traces data frame. The trace must contain interim-look numbers, predictive probabilities, decision thresholds, and decisions.

Value

The simulation traces, invisibly.

Details

The upper shaded region represents ppp_stop_now > immediate_success_threshold; the middle region represents success_threshold < ppp_stop_now <= immediate_success_threshold. Futility applies below or at the expected-success threshold when the maximum-sample-size prediction is strictly below its threshold. A legacy trace without immediate_success_threshold is treated as if that threshold were one, which disables immediate success.

Examples

traces <- data.frame(
  trial = 1:6,
  look = rep(c(1, 2), each = 3),
  planned_N = rep(c(40, 60), each = 3),
  ppp_stop_now = c(0.96, 0.4, 0.2, 0.92, 0.5, 0.1),
  success_threshold = rep(c(0.95, 0.9), each = 3),
  immediate_success_threshold = 0.99,
  ppp_success_at_max = c(0.8, 0.5, 0.02, 0.85, 0.4, 0.01),
  futility_threshold = 0.05,
  decision = c(
    "stop_expected_success", "continue", "stop_futility",
    "stop_expected_success", "continue", "stop_futility"
  )
)
plot_sim_decisions(traces)