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This class defines the R-learner of Xie and Wager (2021) for estimation of the conditional average treatment effect.

Format

An R6 class with public methods to initialize the learner, create a regression task, and access the base learner.

Details

For continuous treatment, this implementation follows the partially linear effect-model view in which the outcome regression is decomposed using an A * tau(X) term rather than a fully general treatment-response surface.

When the chosen modifier set V is a strict subset of the adjustment set W, the natural target is E[Y(1) - Y(0) | V] = E[tau(W) | V]. The current implementation does not generally target that object in the reduced-modifier setting. Instead, it learns the overlap-weighted projection f_R(V) = E[Var(A|W) tau(W) | V] / E[Var(A|W) | V], which simplifies to E[e(W)(1-e(W)) tau(W) | V] / E[e(W)(1-e(W)) | V] for binary treatment.

Super classes

sl3::Lrnr_base -> hte3::Lrnr_hte -> Lrnr_cate_R