The S-Learner (Output 3) reports that the interaction term treatment × annual_spend is not statistically significant (p = 0.405). The causal forest (Output 4) reports that annual_spend has the highest variable importance score (0.518) for treatment effect heterogeneity. Evaluate the following statements. Select ALL that are correct.多项选择题

The insignificant interaction term in the S-Learner means that annual spending does not meaningfully influence how customers respond to the email. The causal forest's high importance score for this variable likely reflects overfitting.

These results are consistent with a scenario in which annual spending moderates the treatment effect in a nonlinear way — for instance, if the email increases spending among mid-range customers but has little or negative effect on both very low and very high spenders.

For the purpose of building a customer targeting policy, the causal forest's individual-level estimates are more appropriate than the S-Learner's because the causal forest can capture treatment effect patterns that the parametric model structurally cannot represent.

The fact that the S-Learner and the causal forest produce nearly identical average treatment effects confirms that both methods are equally reliable for ranking individual customers by their expected response to the email.