Asymptotic Validity and Finite-Sample Properties of Approximate Randomization Tests

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Main Author: Toulis, Panos
Format: Preprint
Published: 2019
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author Toulis, Panos
author_facet Toulis, Panos
contents Randomization tests rely on simple data transformations and possess an appealing robustness property. In addition to being finite-sample valid if the data distribution is invariant under the transformation, these tests can be asymptotically valid under a suitable studentization of the test statistic, even if the invariance does not hold. However, practical implementation often encounters noisy data, resulting in approximate randomization tests that may not be as robust. In this paper, our key theoretical contribution is a non-asymptotic bound on the discrepancy between the size of an approximate randomization test and the size of the original randomization test using noiseless data. This allows us to derive novel conditions for the validity of approximate randomization tests under data invariances, while being able to leverage existing results based on studentization if the invariance does not hold. We illustrate our theory through several examples, including tests of significance in linear regression. Our theory can explain certain aspects of how randomization tests perform in small samples, addressing limitations of prior theoretical results.
format Preprint
id arxiv_https___arxiv_org_abs_1908_04218
institution arXiv
publishDate 2019
record_format arxiv
spellingShingle Asymptotic Validity and Finite-Sample Properties of Approximate Randomization Tests
Toulis, Panos
Methodology
Machine Learning
Randomization tests rely on simple data transformations and possess an appealing robustness property. In addition to being finite-sample valid if the data distribution is invariant under the transformation, these tests can be asymptotically valid under a suitable studentization of the test statistic, even if the invariance does not hold. However, practical implementation often encounters noisy data, resulting in approximate randomization tests that may not be as robust. In this paper, our key theoretical contribution is a non-asymptotic bound on the discrepancy between the size of an approximate randomization test and the size of the original randomization test using noiseless data. This allows us to derive novel conditions for the validity of approximate randomization tests under data invariances, while being able to leverage existing results based on studentization if the invariance does not hold. We illustrate our theory through several examples, including tests of significance in linear regression. Our theory can explain certain aspects of how randomization tests perform in small samples, addressing limitations of prior theoretical results.
title Asymptotic Validity and Finite-Sample Properties of Approximate Randomization Tests
topic Methodology
Machine Learning
url https://arxiv.org/abs/1908.04218