Extract an experimental common-environment / maternal variance-ratio interval — common_env_proportion

Usage

common_env_proportion_interval(object, ...)

maternal_proportion_interval(object, ...)

Arguments

object: A fitted model object.
...: Unused. Extra arguments, including level, are an error because they would be ignored; the interval level is fixed at the engine value.

Value

A one-row data frame with estimate (the ratio), lower, upper, level, se, lower_clamped, upper_clamped, and boundary, plus an "interpretation" attribute, for two-effect hsquared_fit objects that contain it.

Details

common_env_proportion_interval() and maternal_proportion_interval() return an experimental large-sample (logit delta-method) confidence interval for the second variance ratio (c2 / m2, ratio2) of the opt-in two-effect model, available only when the fit contains it. On the same two-effect fit, heritability_interval() returns the matching interval for the direct heritability (h2, ratio1).

This mirrors the engine row V3-TWOEFFECT-REML: the interval is the asymptotic delta-method CI built from the two-effect REML observed information (the central finite-difference Hessian of the two-effect REML log-likelihood at the optimum, fd_step = 1e-4). That is not the univariate average-information matrix; see the information-matrix table on Can I fit and report this?. It is asymptotic, delta-method, REML only, and NOT coverage-calibrated – on small samples the REML surface is flat and the interval is unreliable (the parametric bootstrap is the only finite-sample- aware path). No calibrated coverage is claimed.

Boundary honesty: when the ratio's variance component sits on the boundary (sigma -> 0) it is flagged (boundary = TRUE) and lower/upper are NA, never a spuriously tight CI. lower_clamped/upper_clamped flag when a bound reaches the numerical (0, 1) rails.

Falconer fence: c2 / m2 is a variance ratio, not a heritability (see common_env_proportion() / maternal_proportion()).