| The CATE function tau(x) = E[Y(1) - Y(0) | X = x] describes how a treatment’s effect varies across kinds of units, which is what a targeting decision actually needs: a program with a positive average effect can still be wasted on segments where its effect is zero or negative. |
Industry calls estimating tau(x) uplift modeling, and sorts customers into persuadables (target them), sure things and lost causes (spending on them is waste), and do-not-disturbs (contact backfires). Meta-learners (S-, T-, X-learners) and causal forests are the standard estimators. The caveat: a CATE model inherits the identification of its training data, so heterogeneity modeling layers on top of a randomized experiment or a defensible unconfoundedness argument, never in place of one.
