To help countries and researchers address the complex challenges of measuring people on the move, UNECE today released a study on using new data sources to measure international migration, ahead of World Migration Day (December 18). .
Migration is an emotional topic that is at the center of many policy arenas. Policy decisions about migration management rely on statistical evidence, but producing this evidence is notoriously difficult. By definition, migrants are mobile, and therefore tend to be hard to find and count; especially those migrating without legal documentation, who may deliberately or inadvertently avoid being recorded in standard data sources.
Global initiatives, including the 2030 Agenda for Sustainable Development and the 2018 Global Compact for Safe, Orderly and Regular Migration, highlight the need for data to help the world address the many challenges posed by large-scale migration and other forms of cross-border mobility. These global agendas, combined with a growing demand for detailed and timely data on migration from national decision-makers, have prompted the official statistics community to look for new ways to meet data needs. The new UNECE study, in turn, responds to requests from official statisticians to examine the state of the art in using these new approaches.
As the study explains, measuring migration involves both measuring the movements of people in and out of countries, and discovering the numbers and characteristics of those migrants. Conventional data sources include censuses, household surveys, and administrative records (sources of data collected by authorities for purposes other than statistics, such as health, education, and tax records), each with its own pros and cons. A census, for example, only takes place every ten years in most countries, so while it can provide a rich and comprehensive picture of where and how migrant communities live, it cannot be relied upon for up-to-date information on large and sudden changes such as refugee movements in response to a crisis. Administrative sources are much better at capturing changes in real time, but risk missing out on those who fall under the radar of a country’s administrative systems, which could lead to systematic bias as these are often the poorest, most young and more vulnerable.
Integrating information gleaned from these sources is often proposed as a way to overcome such problems, but it’s not a perfect solution. In emergency situations, such as disasters, conflicts and health crises, new and different sources are needed to provide data to understand the rapid changes. The sudden and widespread restrictions on international travel introduced at the onset of the COVID-19 pandemic have shone a spotlight on the limitations of existing migration data sources and methods.
This is where unconventional sources come into play. Data gathered from the use of cell phones, credit cards and social networks – generally known as big data – could be useful for producing migration statistics when used in conjunction with conventional sources. There are many obstacles standing in the way: accessibility, accuracy and access to these new sources. But in recent years, some examples have emerged that highlight its potential.
Examine the use of new sources
With the international official statistical community more eager than ever to investigate the potential offered by these new sources and techniques, the UNECE undertook a study into current and planned uses of new data sources to produce official statistics on migration, a world first on this topic.
Conducted between 2019 and 2021 by an international task force of experts, the study surveyed participating countries to find out which data sources they use and how; the challenges they encountered and what they had learned; and the reasons behind their decisions to continue or stop working with these new sources.
This revealed several examples of successful testing or using new data sources to produce migration statistics; or to complement traditional data sources or, in some cases, to replace them, for example when exceptional circumstances have affected the availability of conventional data sources. For example, when Puerto Rico was hit by Hurricane Maria in 2017, a devastating storm that caused extensive damage and loss of life and resulted in mass emigration from Puerto Rico to the continental United States. The usual method of measuring migration—using annual household surveys—was inadequate because these surveys could not capture the sudden, large-scale movement of people, and in the chaotic aftermath of the hurricane the ability to carry out these surveys was hampered. To fill the gap, the US Census Bureau combined survey data with information on passenger flights between the continental US and Puerto Rico, produced by the US Bureau of Transportation Statistics, to produce “combined” migration estimates.
Addressing obstacles to progress
While the potential of big data sources is considerable, the study found that in reality around three-quarters of participating countries are not currently using them to measure migration because the barriers to effective use are still too high. Countries have cited privacy concerns and legal constraints that place limits on statistical uses of the data. Yet a third of countries reported using new sources to produce statistics on topics other than migration. This suggests that there may still be a role for such sources for migration statistics in the future if these barriers can be overcome.
Overall, the study finds that statistics offices see continued potential in pursuing new data sources to meet urgent and emerging migration data needs. They could help bridge the gap between the need for quick responses to topical migration issues, on the one hand, and the often long delays between data collection and the release of figures using traditional techniques, on the other.
Many countries are moving towards integrated statistical systems and new data sources could be an important component of these, potentially serving as benchmarks against which the quality of other information can be checked.
One thing the study identified as a crucial missing piece in moving towards better exploiting these new sources is that countries share information about their tools, methods and learning. With this in mind, in conjunction with the study, UNECE developed an online repository of innovations in migration statistics, pooling scientific papers and case studies that could help both official statisticians and researchers.
Covering a range of migration topics including international migration, internal migration, human mobility, population movement and population distribution, the tool will grow as countries’ experiences become broader and more complex, with the aim of becoming a key reference supporting the use of new data sources and related methods to produce the migration statistics of the future.