Generalized Sequential Monte Carlo Sampling for Redistricting Simulation

Fuente: arXiv
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Hauptverfasser: O'Sullivan, Philip, Imai, Kosuke, McCartan, Cory
Format: Preprint
Veröffentlicht: 2026
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author O'Sullivan, Philip
Imai, Kosuke
McCartan, Cory
author_facet O'Sullivan, Philip
Imai, Kosuke
McCartan, Cory
contents Simulation methods have become important tools for quantifying partisan and racial bias in redistricting plans. We generalize the Sequential Monte Carlo (SMC) algorithm of McCartan and Imai (2023), one of the commonly used approaches. First, our generalized SMC (gSMC) algorithm can split off regions of arbitrary size, rather than a single district as in the original SMC framework, enabling the sampling of multi-member districts. Second, the gSMC algorithm can operate over various sampling spaces, providing additional computational flexibility. Third, we derive optimal-variance incremental weights and show how to compute them efficiently for each sampling space. Finally, we incorporate Markov chain Monte Carlo (MCMC) steps, creating a hybrid gSMC-MCMC algorithm that can be used for large-scale redistricting applications. We demonstrate the effectiveness of the proposed methodology through analyses of the Irish Parliament, which uses multi-member districts, and the Pennsylvania House of Representatives, which has more than 200 single-member districts.
format Preprint
id arxiv_https___arxiv_org_abs_2603_22188
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Generalized Sequential Monte Carlo Sampling for Redistricting Simulation
O'Sullivan, Philip
Imai, Kosuke
McCartan, Cory
Applications
Computers and Society
Probability
Simulation methods have become important tools for quantifying partisan and racial bias in redistricting plans. We generalize the Sequential Monte Carlo (SMC) algorithm of McCartan and Imai (2023), one of the commonly used approaches. First, our generalized SMC (gSMC) algorithm can split off regions of arbitrary size, rather than a single district as in the original SMC framework, enabling the sampling of multi-member districts. Second, the gSMC algorithm can operate over various sampling spaces, providing additional computational flexibility. Third, we derive optimal-variance incremental weights and show how to compute them efficiently for each sampling space. Finally, we incorporate Markov chain Monte Carlo (MCMC) steps, creating a hybrid gSMC-MCMC algorithm that can be used for large-scale redistricting applications. We demonstrate the effectiveness of the proposed methodology through analyses of the Irish Parliament, which uses multi-member districts, and the Pennsylvania House of Representatives, which has more than 200 single-member districts.
title Generalized Sequential Monte Carlo Sampling for Redistricting Simulation
topic Applications
Computers and Society
Probability
url https://arxiv.org/abs/2603.22188