Measuring Global Migration Flows using Online Data

Abstract

Existing estimates of human migration are limited in their scope, reliability, and timeliness, prompting the United Nations and the Global Compact on Migration to call for improved data collection. Using privacy protected records from three billion Facebook users, we estimate country-to-country migration flows at monthly granularity for 181 countries, accounting for selection into Facebook usage. Our estimates closely match high-quality measures of migration where available but can be produced nearly worldwide and with less delay than alternative methods. We estimate that 39.1 million people migrated internationally in 2022 (0.63% of the population of the countries in our sample). Migration flows significantly changed during the COVID-19 pandemic, decreasing by 64% before rebounding in 2022 to a pace 24% above the pre-crisis rate. We also find that migration from Ukraine increased tenfold in the wake of the Russian invasion. To support research and policy interventions, we will release these estimates publicly through the Humanitarian Data Exchange.

Figures (4)

• Figure 1: Global international migration over time. The dashed line depicts the estimated level of migration in each month, following the procedure described in SI Algorithm to detect migrants using the selection rate weights described in SI Weighting. The solid line smooths the data over a three-month window with one month on each side of the current month.
• Figure 2: Estimated international migration flows in 2022, in millions of people. (A) International migration flows between and within regions in 2022. Lines measure aggregate flows between all country pairs in each region. (B) Top and bottom five countries by annual net migration in 2022. Orange bars depict countries with net emigration, blue bars depict those with net immigration. (C) Top five countries by annual gross migration inflows in 2022. (D) Top five countries by annual gross migration outflows in 2022. (E) Top five (directed) country pairs for annual migration in 2022.
• Figure 3: Migration Flows and COVID-19 policy stringency. (A) Changes in immigration flows during October 2020 and April 2021, relative to each country's 2019 average. Countries are divided into three types based on their quadrant in this plot. (B) Global migration and the mean COVID-19 policy stringency index over time. (C) Migration inflows (solid lines) and COVID-19 stringency (dashed line) for Niger and Haiti (two "Type 1" countries where restrictions were relatively low throughout the sample period). (D) Migration inflows and COVID-19 stringency for France and Slovakia (two "Type 2" countries where restrictions were relaxed and then tightened). (E) Migration inflows and COVID-19 stringency for Australia and Argentina (two "Type 3" countries where restrictions were relatively high throughout the sample period).
• Figure 4: Reported country-to-country migration flows vs. Facebook estimates in thousands. (A) Validation of Facebook estimates against 2019 annual data from the New Zealand Statistical Office. Each point stands for the number of immigrants from a country of origin to New Zealand in 2019. (B) Validation of Facebook estimates against 2019 annual data from Eurostat, the statistical office of the European Union. Each point stands for the number of immigrants from a country of origin to one European country in 2019. (C) Validation of Facebook estimates of monthly migration from India to New Zealand using data from the New Zealand Statistical Office.