Fast Algorithms for Exact Confidence Intervals in Randomized Experiments with Binary Outcomes

Fuente: arXiv
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Main Author: Zhang, Peng
Format: Preprint
Published: 2026
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author Zhang, Peng
author_facet Zhang, Peng
contents We construct exact confidence intervals for the average treatment effect in randomized experiments with binary outcomes using sequences of randomization tests. Our approach does not rely on large-sample approximations and is valid for all sample sizes. Under a balanced Bernoulli design or a matched-pairs design, we show that exact confidence intervals can be computed using only $O(\log n)$ randomization tests, yielding an exponential reduction in the number of tests compared to brute-force. We further prove an information-theoretic lower bound showing that this rate is optimal. In contrast, under balanced complete randomization, the most efficient known procedures require $O(n\log n)$ randomization tests (Aronow et al., 2023), establishing a sharp separation between these designs. In addition, we extend our algorithm to general Bernoulli designs using $O(n^2)$ randomization tests.
format Preprint
id arxiv_https___arxiv_org_abs_2602_20498
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Fast Algorithms for Exact Confidence Intervals in Randomized Experiments with Binary Outcomes
Zhang, Peng
Methodology
We construct exact confidence intervals for the average treatment effect in randomized experiments with binary outcomes using sequences of randomization tests. Our approach does not rely on large-sample approximations and is valid for all sample sizes. Under a balanced Bernoulli design or a matched-pairs design, we show that exact confidence intervals can be computed using only $O(\log n)$ randomization tests, yielding an exponential reduction in the number of tests compared to brute-force. We further prove an information-theoretic lower bound showing that this rate is optimal. In contrast, under balanced complete randomization, the most efficient known procedures require $O(n\log n)$ randomization tests (Aronow et al., 2023), establishing a sharp separation between these designs. In addition, we extend our algorithm to general Bernoulli designs using $O(n^2)$ randomization tests.
title Fast Algorithms for Exact Confidence Intervals in Randomized Experiments with Binary Outcomes
topic Methodology
url https://arxiv.org/abs/2602.20498