Describe an rbmi Draws Object

Extracts structured metadata from an rbmi draws object, including method, formula, sample count, failures, covariance structure, and (for Bayesian methods) MCMC convergence diagnostics. Returns an S3 object with an informative print() method.

Usage

describe_draws(draws_obj)

Arguments

draws_obj

A draws object returned by rbmi::draws().

Value

An S3 object of class c("describe_draws", "list") containing:

method

Human-readable method name (e.g., "Bayesian (MCMC via Stan)")

method_class

Raw class name: "bayes", "approxbayes", or "condmean"

n_samples

Total number of samples

n_failures

Number of failed samples

formula

Deparsed model formula string

covariance

Covariance structure (e.g., "us")

same_cov

Logical; whether same covariance is used across groups

condmean_type

(condmean only) "jackknife" or "bootstrap"

n_primary

(condmean only) Always 1

n_resampled

(condmean only) Number of resampled draws

bayes_control

(bayes only) List with warmup, thin, chains, seed

mcmc

(bayes with stanfit only) List with rhat, ess, max_rhat, min_ess, n_params, converged

Details

For conditional mean methods, the sample count is displayed as "1 + N" matching the rbmi convention where the first sample is the primary (full-data) fit and the remaining N are jackknife or bootstrap resamples.

For Bayesian methods, MCMC convergence diagnostics (ESS, Rhat) are extracted from the stanfit object when rstan is available. The converged flag uses the Rhat < 1.1 threshold matching rbmi's own convention.

See also

• rbmi::draws() to create draws objects

• rbmi::method_condmean(), rbmi::method_bayes(), rbmi::method_approxbayes() for method specification

Examples

if (FALSE) { # \dontrun{
library(rbmi)
library(dplyr)
data("ADEFF", package = "rbmiUtils")

# Prepare ADEFF data for rbmi pipeline
ADEFF <- ADEFF |>
  mutate(
    TRT = factor(TRT01P, levels = c("Placebo", "Drug A")),
    USUBJID = factor(USUBJID),
    AVISIT = factor(AVISIT, levels = c("Week 24", "Week 48"))
  )

vars <- set_vars(
  subjid = "USUBJID", visit = "AVISIT", group = "TRT",
  outcome = "CHG", covariates = c("BASE", "STRATA", "REGION")
)
dat <- ADEFF |> select(USUBJID, STRATA, REGION, TRT, BASE, CHG, AVISIT)
draws_obj <- draws(
  data = dat, vars = vars,
  method = method_bayes(n_samples = 100)
)

# Inspect the draws object
desc <- describe_draws(draws_obj)
print(desc)

# Programmatic access to metadata
desc$method
desc$n_samples
desc$formula
} # }