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The per-unit counterfactual variance is not identified from the joint density: it depends on the cross-world coupling of the structural residuals under the factual and counterfactual treatments, which no goodness-of-fit can certify. This accessor therefore raises an error rather than return the (misleading) spread of the abduction atoms.

Usage

gmm_cf_variance(x)

Arguments

x

A gmm_counterfactual_law.

Value

Never returns; always raises a proxymix_not_identified error.

Examples

g <- gmm(weights = 1, means = list(c(0, 0, 0)),
         covariances = list(diag(3)))
cf <- gmm_counterfactual(g, evidence = c(1, 0, 0.2),
                         do = c(NA, 1, NA), query = 1L)
try(gmm_cf_variance(cf))
#> Error in gmm_cf_variance(cf) : 
#>   The individual counterfactual variance is not identified.
#>  It depends on the unidentified cross-world coupling of the structural
#>   residuals.
#>  Only the counterfactual mean is identified; see `gmm_cf_mean()`.