From First Principles to Multi-scale Decomposition:Mutual Information as a Segregation Index

Fuente: arXiv
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Main Authors: Sahasrabuddhe, Rohit, Lambiotte, Renaud
Format: Preprint
Published: 2025
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author Sahasrabuddhe, Rohit
Lambiotte, Renaud
author_facet Sahasrabuddhe, Rohit
Lambiotte, Renaud
contents Segregation is a multi-scale phenomenon that requires careful measurement. A segregation index implicitly defines how the demographic compositions of locations are compared. We identify two properties -- mean-minimisation and invariance -- that uniquely characterise the Kullback-Leibler divergence as a measure of demographic difference. Mean-minimiser makes the comparison consistent with population aggregation and invariance ensures that it behaves intuitively under demographic coarse-graining. The corresponding segregation index is mutual information, which can be decomposed across geographic and demographic scales to identify the contributions of regions and supergroups. We demonstrate how this reveals insights into ethnic residential segregation in England and Wales that would be inaccessible otherwise. By deriving mutual information from first principles, we identify situations in which it is the only suitable segregation index, and provide open source software to support multi-scale analysis.
format Preprint
id arxiv_https___arxiv_org_abs_2511_23069
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle From First Principles to Multi-scale Decomposition:Mutual Information as a Segregation Index
Sahasrabuddhe, Rohit
Lambiotte, Renaud
Physics and Society
Segregation is a multi-scale phenomenon that requires careful measurement. A segregation index implicitly defines how the demographic compositions of locations are compared. We identify two properties -- mean-minimisation and invariance -- that uniquely characterise the Kullback-Leibler divergence as a measure of demographic difference. Mean-minimiser makes the comparison consistent with population aggregation and invariance ensures that it behaves intuitively under demographic coarse-graining. The corresponding segregation index is mutual information, which can be decomposed across geographic and demographic scales to identify the contributions of regions and supergroups. We demonstrate how this reveals insights into ethnic residential segregation in England and Wales that would be inaccessible otherwise. By deriving mutual information from first principles, we identify situations in which it is the only suitable segregation index, and provide open source software to support multi-scale analysis.
title From First Principles to Multi-scale Decomposition:Mutual Information as a Segregation Index
topic Physics and Society
url https://arxiv.org/abs/2511.23069