Optimal Dorfman Group Testing for Symmetric Distributions

Fuente: arXiv
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Autores principales: Landolfi, Nicholas C., Lall, Sanjay
Formato: Preprint
Publicado: 2023
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author Landolfi, Nicholas C.
Lall, Sanjay
author_facet Landolfi, Nicholas C.
Lall, Sanjay
contents We study Dorfman's classical group testing protocol in a novel setting where individual specimen statuses are modeled as exchangeable random variables. We are motivated by infectious disease screening. In that case, specimens which arrive together for testing often originate from the same community and so their statuses may exhibit positive correlation. Dorfman's protocol screens a population of n specimens for a binary trait by partitioning it into non-overlapping groups, testing these, and only individually retesting the specimens of each positive group. The partition is chosen to minimize the expected number of tests under a probabilistic model of specimen statuses. We relax the typical assumption that these are independent and identically distributed and instead model them as exchangeable random variables. In this case, their joint distribution is symmetric in the sense that it is invariant under permutations. We give a characterization of such distributions in terms of a function q where q(h) is the marginal probability that any group of size h tests negative. We use this interpretable representation to show that the set partitioning problem arising in Dorfman's protocol can be reduced to an integer partitioning problem and efficiently solved. We apply these tools to an empirical dataset from the COVID-19 pandemic. The methodology helps explain the unexpectedly high empirical efficiency reported by the original investigators.
format Preprint
id arxiv_https___arxiv_org_abs_2308_11050
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Optimal Dorfman Group Testing for Symmetric Distributions
Landolfi, Nicholas C.
Lall, Sanjay
Applications
Probability
Methodology
60G09, 62E10, 62H05, 62P10, 90-08, 90C39, 90C90
We study Dorfman's classical group testing protocol in a novel setting where individual specimen statuses are modeled as exchangeable random variables. We are motivated by infectious disease screening. In that case, specimens which arrive together for testing often originate from the same community and so their statuses may exhibit positive correlation. Dorfman's protocol screens a population of n specimens for a binary trait by partitioning it into non-overlapping groups, testing these, and only individually retesting the specimens of each positive group. The partition is chosen to minimize the expected number of tests under a probabilistic model of specimen statuses. We relax the typical assumption that these are independent and identically distributed and instead model them as exchangeable random variables. In this case, their joint distribution is symmetric in the sense that it is invariant under permutations. We give a characterization of such distributions in terms of a function q where q(h) is the marginal probability that any group of size h tests negative. We use this interpretable representation to show that the set partitioning problem arising in Dorfman's protocol can be reduced to an integer partitioning problem and efficiently solved. We apply these tools to an empirical dataset from the COVID-19 pandemic. The methodology helps explain the unexpectedly high empirical efficiency reported by the original investigators.
title Optimal Dorfman Group Testing for Symmetric Distributions
topic Applications
Probability
Methodology
60G09, 62E10, 62H05, 62P10, 90-08, 90C39, 90C90
url https://arxiv.org/abs/2308.11050