Search Results for author: Xiaojie Mao

Found 17 papers, 7 papers with code

Source Condition Double Robust Inference on Functionals of Inverse Problems

no code implementations25 Jul 2023 Andrew Bennett, Nathan Kallus, Xiaojie Mao, Whitney Newey, Vasilis Syrgkanis, Masatoshi Uehara

We consider estimation of parameters defined as linear functionals of solutions to linear inverse problems.

Learning under Selective Labels with Data from Heterogeneous Decision-makers: An Instrumental Variable Approach

no code implementations13 Jun 2023 Jian Chen, Zhehao Li, Xiaojie Mao

The labeled data distribution may substantially differ from the full population, especially when the historical decisions and the target outcome can be simultaneously affected by some unobserved factors.

Decision Making Selection bias

Online Joint Assortment-Inventory Optimization under MNL Choices

no code implementations4 Apr 2023 Yong Liang, Xiaojie Mao, Shiyuan Wang

We study an online joint assortment-inventory optimization problem, in which we assume that the choice behavior of each customer follows the Multinomial Logit (MNL) choice model, and the attraction parameters are unknown a priori.

Decision Making

Inference on Strongly Identified Functionals of Weakly Identified Functions

no code implementations17 Aug 2022 Andrew Bennett, Nathan Kallus, Xiaojie Mao, Whitney Newey, Vasilis Syrgkanis, Masatoshi Uehara

In a variety of applications, including nonparametric instrumental variable (NPIV) analysis, proximal causal inference under unmeasured confounding, and missing-not-at-random data with shadow variables, we are interested in inference on a continuous linear functional (e. g., average causal effects) of nuisance function (e. g., NPIV regression) defined by conditional moment restrictions.

Causal Inference regression +1

Doubly Robust Distributionally Robust Off-Policy Evaluation and Learning

1 code implementation19 Feb 2022 Nathan Kallus, Xiaojie Mao, Kaiwen Wang, Zhengyuan Zhou

Thanks to a localization technique, LDR$^2$OPE only requires fitting a small number of regressions, just like DR methods for standard OPE.

Off-policy evaluation

Long-term Causal Inference Under Persistent Confounding via Data Combination

no code implementations15 Feb 2022 Guido Imbens, Nathan Kallus, Xiaojie Mao, Yuhao Wang

In this paper, we uniquely tackle the challenge of persistent unmeasured confounders, i. e., some unmeasured confounders that can simultaneously affect the treatment, short-term outcomes and the long-term outcome, noting that they invalidate identification strategies in previous literature.

Causal Inference

Causal Inference Under Unmeasured Confounding With Negative Controls: A Minimax Learning Approach

no code implementations25 Mar 2021 Nathan Kallus, Xiaojie Mao, Masatoshi Uehara

Previous work has relied on completeness conditions on these functions to identify the causal parameters and required uniqueness assumptions in estimation, and they also focused on parametric estimation of bridge functions.

Causal Inference

Fast Rates for Contextual Linear Optimization

no code implementations5 Nov 2020 Yichun Hu, Nathan Kallus, Xiaojie Mao

While one may use off-the-shelf machine learning methods to separately learn a predictive model and plug it in, a variety of recent methods instead integrate estimation and optimization by fitting the model to directly optimize downstream decision performance.

Decision Making

Stochastic Optimization Forests

1 code implementation17 Aug 2020 Nathan Kallus, Xiaojie Mao

We study contextual stochastic optimization problems, where we leverage rich auxiliary observations (e. g., product characteristics) to improve decision making with uncertain variables (e. g., demand).

Decision Making Stochastic Optimization

On the role of surrogates in the efficient estimation of treatment effects with limited outcome data

no code implementations27 Mar 2020 Nathan Kallus, Xiaojie Mao

However, there is often an abundance of observations on surrogate outcomes not of primary interest, such as short-term health effects or online-ad click-through.

Marketing

Localized Debiased Machine Learning: Efficient Inference on Quantile Treatment Effects and Beyond

1 code implementation30 Dec 2019 Nathan Kallus, Xiaojie Mao, Masatoshi Uehara

A central example is the efficient estimating equation for the (local) quantile treatment effect ((L)QTE) in causal inference, which involves as a nuisance the covariate-conditional cumulative distribution function evaluated at the quantile to be estimated.

BIG-bench Machine Learning Causal Inference

Smooth Contextual Bandits: Bridging the Parametric and Non-differentiable Regret Regimes

1 code implementation5 Sep 2019 Yichun Hu, Nathan Kallus, Xiaojie Mao

We study a nonparametric contextual bandit problem where the expected reward functions belong to a H\"older class with smoothness parameter $\beta$.

Multi-Armed Bandits

Assessing Algorithmic Fairness with Unobserved Protected Class Using Data Combination

1 code implementation1 Jun 2019 Nathan Kallus, Xiaojie Mao, Angela Zhou

In this paper we study a fundamental challenge to assessing disparate impacts in practice: protected class membership is often not observed in the data.

Fairness

Fairness Under Unawareness: Assessing Disparity When Protected Class Is Unobserved

1 code implementation27 Nov 2018 Jiahao Chen, Nathan Kallus, Xiaojie Mao, Geoffry Svacha, Madeleine Udell

We also propose an alternative weighted estimator that uses soft classification, and show that its bias arises simply from the conditional covariance of the outcome with the true class membership.

Decision Making Fairness +2

Interval Estimation of Individual-Level Causal Effects Under Unobserved Confounding

no code implementations5 Oct 2018 Nathan Kallus, Xiaojie Mao, Angela Zhou

We study the problem of learning conditional average treatment effects (CATE) from observational data with unobserved confounders.

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