Proximity Matters: Local Proximity Preserved Balancing for Treatment Effect Estimation
<|reference_start|>Proximity Matters: Local Proximity Preserved Balancing for Treatment Effect Estimation: Heterogeneous treatment effect (HTE) estimation from observational data poses significant challenges due to treatment selection bias. Existing methods address this bias by minimizing distribution discrepancies between treatment groups in latent space, focusing on global alignment. However, the fruitful aspect of local proximity, where similar units exhibit similar outcomes, is often overlooked. In this study, we propose Proximity-aware Counterfactual Regression (PCR) to exploit proximity for representation balancing within the HTE estimation context. Specifically, we introduce a local proximity preservation regularizer based on optimal transport to depict the local proximity in discrepancy calculation. Furthermore, to overcome the curse of dimensionality that renders the estimation of discrepancy ineffective, exacerbated by limited data availability for HTE estimation, we develop an informative subspace projector, which trades off minimal distance precision for improved sample complexity. Extensive experiments demonstrate that PCR accurately matches units across different treatment groups, effectively mitigates treatment selection bias, and significantly outperforms competitors. Code is available at https://anonymous.4open.science/status/ncr-B697.<|reference_end|>
@article{wang2024proximity,
    title={Proximity Matters: Local Proximity Preserved Balancing for Treatment
  Effect Estimation},
    author={Hao Wang, Zhichao Chen, Yuan Shen, Jiajun Fan, Zhaoran Liu, Degui
  Yang, Xinggao Liu, Haoxuan Li},
    journal={arXiv preprint arXiv:2407.01111},
    year={2024},
    archivePrefix={arXiv},
    eprint={2407.01111},
    primaryClass={cs.LG cs.AI stat.ML}
}