Quality assessment and community detection methods for anonymized mobility data in the Italian Covid context

Jules Morand*, Shoichi Yip, Yannis Velegrakis, Gianluca Lattanzi, Raffaello Potestio, Luca Tubiana

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

We discuss how to assess the reliability of partial, anonymized mobility data and compare two different methods to identify spatial communities based on movements: Greedy Modularity Clustering (GMC) and the novel Critical Variable Selection (CVS). These capture different aspects of mobility: direct population fluxes (GMC) and the probability for individuals to move between two nodes (CVS). As a test case, we consider movements of Italians before and during the SARS-Cov2 pandemic, using Facebook users’ data and publicly available information from the Italian National Institute of Statistics (Istat) to construct daily mobility networks at the interprovincial level. Using the Perron-Frobenius (PF) theorem, we show how the mean stochastic network has a stationary population density state comparable with data from Istat, and how this ceases to be the case if even a moderate amount of pruning is applied to the network. We then identify the first two national lockdowns through temporal clustering of the mobility networks, define two representative graphs for the lockdown and non-lockdown conditions and perform optimal spatial community identification on both graphs using the GMC and CVS approaches. Despite the fundamental differences in the methods, the variation of information (VI) between them assesses that they return similar partitions of the Italian provincial networks in both situations. The information provided can be used to inform policy, for example, to define an optimal scale for lockdown measures. Our approach is general and can be applied to other countries or geographical scales.

Original languageEnglish
Article number4636
Number of pages13
JournalScientific Reports
Volume14
Issue number1
DOIs
Publication statusPublished - 26 Feb 2024

Fingerprint

Dive into the research topics of 'Quality assessment and community detection methods for anonymized mobility data in the Italian Covid context'. Together they form a unique fingerprint.

Cite this