Test a random-effect variance component — test_random

test_random_effect() exposes the boundary-aware likelihood-ratio route for random-effect variance components. The v1 certified route is a nested ML comparison that adds exactly one variance/covariance parameter and reports the Self-Liang 50:50 mixture reference distribution. It is intentionally separate from test_effect(), which tests fixed effects.

Usage

test_random_effect(
  fit,
  term,
  method = c("boundary_lrt"),
  refit_for_comparison = c("auto", "error", "ml"),
  ...
)

# S3 method for class 'mm_lmm'
test_random_effect(
  fit,
  term,
  method = c("boundary_lrt"),
  refit_for_comparison = c("auto", "error", "ml"),
  ...
)

Arguments

fit: A fitted mm_lmm.
term: Random-effect term to test. This can be the term id ("r0"), the original random-effect fragment such as "(1 | subject)", or a unique grouping factor name such as "subject".
method: Currently "boundary_lrt".
refit_for_comparison: How to handle REML fits. "auto" and "ml" refit to ML; "error" refuses.
...: Reserved for future methods.

Value

An mm_random_effect_test object with a one-row table.