Optimal Conditional Inference in Adaptive Experiments

Fuente: arXiv
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Main Authors: Chen, Jiafeng, Andrews, Isaiah
Format: Preprint
Published: 2023
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author Chen, Jiafeng
Andrews, Isaiah
author_facet Chen, Jiafeng
Andrews, Isaiah
contents We study batched bandit experiments and consider the problem of inference conditional on the realized stopping time, assignment probabilities, and target parameter, where all of these may be chosen adaptively using information up to the last batch of the experiment. Absent further restrictions on the experiment, we show that inference using only the results of the last batch is optimal. When the adaptive aspects of the experiment are known to be location-invariant, in the sense that they are unchanged when we shift all batch-arm means by a constant, we show that there is additional information in the data, captured by one additional linear function of the batch-arm means. In the more restrictive case where the stopping time, assignment probabilities, and target parameter are known to depend on the data only through a collection of polyhedral events, we derive computationally tractable and optimal conditional inference procedures.
format Preprint
id arxiv_https___arxiv_org_abs_2309_12162
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Optimal Conditional Inference in Adaptive Experiments
Chen, Jiafeng
Andrews, Isaiah
Methodology
Machine Learning
Econometrics
Statistics Theory
We study batched bandit experiments and consider the problem of inference conditional on the realized stopping time, assignment probabilities, and target parameter, where all of these may be chosen adaptively using information up to the last batch of the experiment. Absent further restrictions on the experiment, we show that inference using only the results of the last batch is optimal. When the adaptive aspects of the experiment are known to be location-invariant, in the sense that they are unchanged when we shift all batch-arm means by a constant, we show that there is additional information in the data, captured by one additional linear function of the batch-arm means. In the more restrictive case where the stopping time, assignment probabilities, and target parameter are known to depend on the data only through a collection of polyhedral events, we derive computationally tractable and optimal conditional inference procedures.
title Optimal Conditional Inference in Adaptive Experiments
topic Methodology
Machine Learning
Econometrics
Statistics Theory
url https://arxiv.org/abs/2309.12162