Migrant mobility flows characterized with digital data.

Mattia Mazzoli,Natalia Adler,Willian Wives,Pere Colet,José J Ramasco,Boris Diechtiareff,Antònia Tugores,Jordi Paniagua

doi:10.1371/journal.pone.0230264

Abstract

Monitoring migration flows is crucial to respond to humanitarian crisis and to design efficient policies. This information usually comes from surveys and border controls, but timely accessibility and methodological concerns reduce its usefulness. Here, we propose a method to detect migration flows worldwide using geolocated Twitter data. We focus on the migration crisis in Venezuela and show that the calculated flows are consistent with official statistics at country level. Our method is versatile and far-reaching, as it can be used to study different features of migration as preferred routes, settlement areas, mobility through several countries, spatial integration in cities, etc. It provides finer geographical and temporal resolutions, allowing the exploration of issues not contemplated in official records. It is our hope that these new sources of information can complement official ones, helping authorities and humanitarian organizations to better assess when and where to intervene on the ground.

Highlights

Migration is an ubiquitous phenomenon in human history
As shown in the Table, independently of the criteria used the number of Twitter Users which are Venezuelan residents (TUVs) is relatively stable in 2015 and 2016, and we found a decline of over 20% in 2017 and almost 50% in 2018
The migration crisis had the first peak in the last months of 2016, so there is a combination of factors that can explain the drop in the number of TUVs

Summary

Introduction

Migration is an ubiquitous phenomenon in human history. People move to improve living conditions or, to escape social distress [1] and natural disasters [2]. The data showed that the population changes could not be explained by the number of births and deaths alone, another reason had to be involved in the process: migration. Official data on migration flows relies on the comparison of heterogeneous records across countries, which usually have different time scales and time coverage [4]. Surveys and census records are helpful tools for estimating migratory statistics, but the information is not provided at a multinational scale, they are costly and, the update times tend to be long. Looking at a single country, the net population variation, besides changes due to births and deaths, can be calculated as the difference between the number of immigrants and emigrants. Migrants’ mobility, can involve several countries biasing the single-country statistics. There can be multiple entrances in a country by the same individual or several countries along

Methods

Results

Conclusion