Fits Poisson, zero-inflated Poisson (ZIP), and negative binomial (NB) models. Model selection is performed using the Deviance Information Criterion (DIC), Watanabe-Akaike Information Criterion (WAIC), and Pareto-smoothed importance sampling leave-one-out cross-validation (PSIS-LOO). For each criterion, the function applies a parsimony rule that favors the underreported Poisson model when its criterion value is within a specified threshold of the minimum value across the candidate models; otherwise, the model with the minimum criterion value is selected.

urc_mcmc_naive(
  x,
  thresh = 2,
  prior_lambda = "dgamma(0.1, 0.1)",
  prior_c = "dgamma(0.1, 0.1)",
  prior_pi = "dbeta(1, 1)",
  n_iter = 8000,
  n_chains = 2,
  n_burnin = n_iter/2,
  seed = 123,
  inits = NULL,
  parallel = FALSE,
  workers = NULL
)

Arguments

x

A named list containing the data(observed counts) to be passed to the JAGS models.

thresh

Numeric. The threshold used for the parsimony rule. If the underreported Poisson model is within thresh units of the minimum value of a model-selection criterion, the Poisson model is selected as the preferred model; otherwise, the model with the minimum value of the criterion is selected. Applied separately to DIC, WAIC, and PSIS-LOO. Default is 2.

prior_lambda

A prior distribution for the Poisson or ZIP rate parameter lambda.

prior_c

A prior distribution for the dispersion parameter c (NB only).

prior_pi

A prior distribution for the zero-inflation probability pi (ZIP only).

n_iter

Integer. Total number of MCMC iterations per chain.

n_chains

Integer. Number of MCMC chains.

n_burnin

Integer. Number of burn-in iterations to discard.

seed

Integer. Random seed for reproducibility.

inits

Optional. A function or list specifying initial values for the MCMC.

parallel

Logical. If TRUE, model fitting is performed in parallel using the future and furrr frameworks. This enables simultaneous fitting of the Poisson, zero-inflated Poisson, and negative binomial models across multiple workers. If FALSE, the models are fitted sequentially.

Value

A named list containing:

models

A named list of fitted rjags model objects.

dics

A data frame containing the DIC value for each fitted model.

waics

A data frame containing the WAIC value for each fitted model.

loos

A data frame containing the PSIS-LOO value for each fitted model.

dic_best

The preferred model selected using the DIC-based parsimony rule.

waic_best

The preferred model selected using the WAIC-based parsimony rule.

loo_best

The preferred model selected using the PSIS-LOO-based parsimony rule.