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Greg Lewis

6 accepted papers

2021

Estimating the Long-Term Effects of Novel Treatments

NeurIPS 2021poster

Policy makers often need to estimate the long-term effects of novel treatments, while only having historical data of older treatment options. We propose a surrogate-based approach using a long-term dataset where only past treatments were administered and a short-term dataset where novel treatments h…

Cited by 14SourcePDFScholar
2020

Minimax Estimation of Conditional Moment Models

NeurIPS 2020poster

We develop an approach for estimating models described via conditional moment restrictions, with a prototypical application being non-parametric instrumental variable regression. We introduce a min-max criterion function, under which the estimation problem can be thought of as solving a zero-sum gam…

2019

Machine Learning Estimation of Heterogeneous Treatment Effects with Instruments

NeurIPS 2019spotlight

We consider the estimation of heterogeneous treatment effects with arbitrary machine learning methods in the presence of unobserved confounders with the aid of a valid instrument. Such settings arise in A/B tests with an intent-to-treat structure, where the experimenter randomizes over which user wi…

2019

Semi-Parametric Efficient Policy Learning with Continuous Actions

NeurIPS 2019poster

We consider off-policy evaluation and optimization with continuous action spaces. We focus on observational data where the data collection policy is unknown and needs to be estimated from data. We take a semi-parametric approach where the value function takes a known parametric form in the treatment…

2017

Deep IV: A Flexible Approach for Counterfactual Prediction

ICML 2017poster

Counterfactual prediction requires understanding causal relationships between so-called treatment and outcome variables. This paper provides a recipe for augmenting deep learning methods to accurately characterize such relationships in the presence of instrument variables (IVs) – sources of treatmen…