Overview

voiageR is the thin R interface to the voiage Python library. It exposes the stable EVPI, EVPPI, and EVSI wrappers while keeping the package surface small, predictable, and suitable for scripted use.

The examples below are intentionally non-interactive. They show the package shape, the Python environment setup, and the canonical data contracts without requiring the vignette build to depend on a live Python session.

Set up the Python environment

library(voiageR)

set_voiage_env("voiage", type = "virtualenv")
init_voiage()

If you manage Python through Conda, use:

set_voiage_env("voiage", type = "conda")

EVPI

net_benefits <- matrix(
  c(10.0, 12.0, 11.0, 9.0, 13.0, 14.0),
  nrow = 3,
  byrow = TRUE,
  dimnames = list(NULL, c("Strategy A", "Strategy B"))
)

evpi(net_benefits)

EVPPI

parameter_samples <- list(
  effect = c(0.10, 0.12, 0.11),
  cost = c(1000, 980, 1025)
)

evppi(net_benefits, parameter_samples, parameters_of_interest = "effect")

EVSI

model_func <- function(params) {
  cbind(
    Strategy_A = params$effect * 100 - params$cost,
    Strategy_B = params$effect * 110 - params$cost
  )
}

prior_samples <- list(
  effect = c(0.10, 0.12, 0.11),
  cost = c(1000, 980, 1025)
)

trial_design <- list(
  arms = list(
    list(name = "Treatment", sample_size = 50),
    list(name = "Control", sample_size = 50)
  )
)

evsi(
  model_func,
  prior_samples,
  trial_design,
  method = "efficient",
  n_outer_loops = 100,
  n_inner_loops = 1000
)

Current wrapper surface

The current R package exports the core analysis wrappers only:

• evpi() for perfect-information value
• evppi() for parameter-specific information value
• evsi() for sample-information value

Composite metrics such as ENBS are currently part of the Python surface and can be composed from the results above when needed.

Build outputs

The package ships a deterministic PDF manual build helper at tools/build-manual.R. It is designed for non-interactive use from the package root and produces a stable manual artifact from the package Rd files for release packaging and local verification.