Estimated counterfactual (untreated potential outcome) matrix

Returns a method's estimate of the untreated potential outcome \(Y(0)\) as an N x T matrix on the panel's unit/time grid. This gives every estimator a common interface, so counterfactuals – and the unit-period prediction RMSE built on them (panel_rmse() with metric = "prediction") – can be compared on the same footing.

Usage

counterfactual_matrix(object, ...)

predict_counterfactual(object, ...)

Arguments

object: A fitted object: a trop fit, a cf_comparison from panel_compare(), a synthdid estimate, or any object carrying a counterfactual element.
...: Unused; for method extensibility.

Value

For a single fit, an N x T numeric matrix (with NA where the method does not define a counterfactual). For a cf_comparison, a named list of such matrices, one per method.

Details

Coverage of the returned matrix differs by method. The native engines (trop(), and the DID/MC/TROP fits inside panel_compare()) return a fitted value for every cell. Methods whose model only defines a counterfactual for the treated units – DIFP, and (when the optional package is installed) SDID, SC and gsynth – fill the treated rows and leave control cells NA (a control's untreated outcome is simply its observed value).

predict_counterfactual() is an alias for counterfactual_matrix().

Examples

df <- sim_panel(N = 14, T = 9, n_treated = 3, t0 = 6, seed = 1)
fit <- trop(df, "y", "w", "id", "t",
            lambda = list(time = 0.1, unit = 0.5, nn = 2), se = "none")
M <- counterfactual_matrix(fit)
dim(M)
#> [1] 14  9