C OVID - 1 9 a n d M i g r a t i o n i n t h e M e d i t e r r a n e a n R e g i o n
BOX 1.2 Data limitations in measuring migration flows during the COVID-19 pandemic Several of the data sources used in this chapter to explain migration flows come with some limitations. First, several bureaucratic agencies were fully or partially closed during early periods of the pandemic, slowing down the processing of visas, permits, and asylum applications. Second, some of the applications for asylum and visas may have been filed by migrants who were already in Europe when the pandemic struck. Thus, the drops in the processing and issuance of these legal documents may reflect the limited capacity of government agencies to supply migrants with legal documents at that time rather than an actual drop in migration flows or demand for such documents. Second, the use of Facebook’s advertising platform to collect data is a relatively new methodology. Pötzschke and Braun (2017) first used Facebook advertising as a more effective way to target survey participants, and they found this survey methodology could reach previously hard-to-reach populations. Zagheni, Weber, and Gummadi (2017) were among the first to use the Facebook advertising platform to estimate international migrant stocks. Comparing their statistics with the US Census Bureau’s American Community Survey, they conclude that despite some sources of bias, this bias can be estimated and corrected. Figure B1.2.1 Destinations of emigrants from Senegal, by data source a. UN DESA data, 2020
b. Facebook location data, 2021 440 400 360 320 280 240 200 160 120 80 40 0
Coverage (in thousands)
440 400 360 320 280 240 200 160 120 80 40 0
Distribution
Number of migrants
Number of migrants
Distribution
France
Italy
United States
Spain
Canada
Belgium
Germany
Switzerland
Portugal
United Kingdom
Other
Sources: International Migrant Stock 2020 dataset, Population Division, United Nations Department of Economic and Social Affairs (UN DESA): https://www.un.org/development/desa/pd/content/international -migrant-stock; World Bank internal data collection from Facebook’s advertising platform.
(continued on next page)
4 1
