Tighter Prediction Intervals for Causal Outcomes Under Hidden Confounding

Causal inference of exact individual treatment outcomes in the presence of hidden confounders is rarely possible. Instead, recent work has adapted conformal prediction to produce outcome intervals. Unfortunately this family of methods tends to be overly conservative, sometimes giving uninformative intervals. We introduce an alternative approach termed Caus-Modens, for characterizing causal outcome intervals by modulated ensembles. Motivated from Bayesian statistics and ensembled uncertainty quantification, Caus-Modens gives tighter outcome intervals in practice, measured by the necessary interval size to achieve sufficient coverage on three separate benchmarks. The last benchmark is a novel usage of GPT-4 for observational experiments with unknown but probeable ground truth.