Simulate a double-observer abundance data set

Draws from the double_observer() model: site abundance N ~ Poisson(lambda) observed by two observers with detection p1 / p2. For type = "independent" each individual is recorded by observer 1 only, observer 2 only, or both (three cell counts). For type = "dependent" a primary observer records what it detects and a secondary observer records only the primary's misses (two cell counts, primary-detected and secondary-only); the primary observer alternates across sites (role-swapping) so p1 and p2 are identifiable, and the per-site primary indicator is returned as primary.

Usage

simulate_double_observer(
  N = 200,
  type = c("independent", "dependent"),
  n_abund_covs = 1,
  n_det_covs = 1,
  beta_lambda = NULL,
  beta_p1 = NULL,
  beta_p2 = NULL,
  seed = NULL
)

Arguments

N

Number of sites (default 200).

type

"independent" (default) or "dependent" (role-swapping).

n_abund_covs, n_det_covs

Number of abundance / detection covariates.

beta_lambda

Log-abundance coefficients c(intercept, slopes...). Default c(log(8), runif(n_abund_covs, -0.5, 0.5)).

beta_p1, beta_p2

Per-observer detection coefficients (logit). Default moderate detection.

seed

Optional random seed.

Value

A list with y (N x 3 cell counts for "independent", N x 2 for "dependent"), data, primary (the per-site primary observer, for "dependent"), and truth.

Examples

sim <- simulate_double_observer(N = 50, seed = 1)
head(sim$y)