This article was originally published in two parts (part one and part two) on COMPAS at the School of Anthropology of the University of Oxford, by Frank Laczko and Elisa Mosler Vidal.

Part One

This blog has been written in parallel with the release of the latest episode of The Migration Oxford Podcast titled "Global Migration Data: Making Sense of the Numbers".

The UN has been publishing recommendations on how countries should define and measure international migration since 1953. Yet we still know relatively little about global migration. Even though more data are being collected than ever before, we still struggle to answer basic questions. For example, the latest figure for the global number of migrants is for mid-2020, and only 45 countries reported sharing data with the UN on migration flows. In Africa, 17 per cent of countries have not produced official statistics on the number of international migrants since 2005. Why is this? In [part one of] this blog, we explore a few common obstacles to effectively collecting, managing and analysing migration data.

What are some of the key data challenges?

Uneven adherence to definitions 

Migration has been defined in different ways over the years. The 1998 UN recommendations did this comprehensively, defining an international migrant as: 

“any person who changes his or her country of usual residence”, distinguishing between “short-term migrants” – those who change their country of usual residence for at least three months but less than a year – and “long-term migrants” – those who do so for at least one year.” 

While countries are encouraged to follow these recommendations, not all do. Instead, many use different concepts and definitions. For example, some countries use a different minimum duration of stay to define migrants. Out of 36 countries reporting international migration flow data to the OECD in 2018, only 11 used a 12-month definition as internationally recommended.  

This all affects global comparability of data and means we cannot compile national migration data meaningfully; it isn’t possible to compare one country’s migrants statistics with another’s if the way migrants are defined and measured is different.  

The landscape of migration is always changing. To reflect the growing complexity of migration, increasingly we speak not only about migration but also about “human mobility,” a wider concept – for example, including those regularly undertaking cross-border movements for study or work, or living across countries. A process is underway to update the 1998 recommendations to reflect this – revised statistical concepts and definitions are already available.  

Hard-to-measure populations 

Even with official definitions, accurately counting who a migrant is not always straightforward. For example, those with double citizenship are sometimes double counted in different countries, and will be recorded differently depending on which passport they use. The three authors of this book have five countries of citizenships between them – the UK, Hungary, Spain, Germany and Italy – by marriage two more – France and Brazil – and live in two further countries of residence – Switzerland and the US. What does this mean for how they are counted? People live increasingly complex lives.  

Some migrant populations are especially hard to reach with classic data collection methods. For example, unaccompanied minors, homeless migrants and irregular migrants, who may be at particular risk of poor wellbeing, do not always appear in official statistics. Often they are not included in survey or census sampling frames, or are excluded from population registers and residence permits. Seasonal workers who may not change their primary place of residence may also be statistically invisible. Some migrants may be unwilling to be included in data collection exercises, for fear of possible detection or deportation by law enforcement.  

Fragmentation and poor coordination 

In any given country, different types of migration data is collected from across areas of government and through everyday civic and administrative life, and additionally through regular statistical exercises like surveys and censuses. Often migration data producers (such as National Statistical Offices, or NSOs) don’t interact regularly with migration data users (such as a health ministry). Without a special structure, such as a working group, it is difficult for the right people to convene and collaborate regularly to share, discuss and improve migration information  

This can lead to a high degree of fragmentation in data, which makes it harder to get a full picture of migration trends as each data source can only provide information about specific aspects of the phenomenon. This fragmentation in migration data explains much of the limited understanding of migration that we have today. Some countries have used innovative methods to integrate information. Canada’s Longitudinal Immigration Database (IMDB) connects data on immigration and citizenship with longitudinal data on socioeconomic outcomes.  

Limited capacity 

Another challenge is governments’ limited capacity related to migration data, as many lack capacities to generate quality migration statistics. Issues can look like anything from not having advanced enough statistical analysis software, to staff not having all the knowledge necessary to, for example, integrate data protection considerations. Migration data may be given insufficient priority, meaning that in turn, funding to improve it is limited.  

Part Two

Good migration data is essential if migration is to be managed effectively. The Global Compact for Migration urges all countries to improve migration data to ensure that policies are “evidence-based”, but does not spell out in detail how could this be done. In [part two of] this blog we suggest four ways in which to significantly improve data on global migration, at relatively low cost over the next decade.  

1. Make use of existing data 

A considerable amount of migration data is available at national level from administrative sources, surveys and censuses, as well as data arising from the use of new technologies. Given the limited resources often available for migration data, a useful first step would be for each country to comprehensively map out what data are collected already, analyse how this information is shared and used, and propose ways to make better use of existing data sources.  

This will also require new partnerships between the public and private sectors. This is because today an increasing amount of data relating to the movement of people across borders is collected by the private sector. One promising approach to developing effective public-private data partnerships is to create “Data Collaboratives.” These collaboratives enable public and private actors to come together to develop an agreed framework to collect, process, analyse and use data. 

2. Launch a new global migration survey and leverage existing surveys 

One key way in which to boost understanding of the situation of migrants around the world, proposed by many scholars, would be to launch a “World Migration Survey”. Each country would conduct a nationally representative survey of migrants using at least a standard set of core questions. Conducting such a global survey could provide information on subjects that traditional migration sources fail to capture well, such as emigrant stocks, migrant flows, return migration and temporary forms of migration.  

A less costly option in the short term would be to add more migration questions to existing surveys. The International Labour Organization (ILO) and World Bank, for example, has developed new guidance for NSOs on how to add questions relating to migrant recruitment costs to existing labour force surveys. If surveys are large enough to identify a representative sample of migrants, adding a simple question on country of birth or citizenship can help generate new information on migration. 

3. Create a global migration data capacity development programme  

While there have been many calls to enhance countries’ capacities to collect, manage and use migration data, there is as yet no comprehensive, coherent global migration data capacity building programme. Often guides are being produced but not being fully used because of a lack of investment in providing training. A new global migration data capacity-building programme is needed, which is  focused on data collection, analysis and use as well as data protection. 

4. Monitor progress made towards clear goals 

A plethora of recommendations have been made over the years on how to improve migration statistics, but too often there has been little systematic monitoring of the implementation of such recommendations. What is needed is agreement on a broad set of indicators which could be used to monitor progress towards the implementation of recommendations which aim to improve the collection, analysis and responsible use of migration data. 

Concluding Remarks 

Little political priority is often given to collecting timely reliable data on migration. This means that spending can be low in this area. Aside from implementing these recommendations, much greater investment into data is needed. This supports policy and pays off: every US dollar invested in data leads to benefits of an average of USD 32. 

There have been calls to improve global migration statistics for several decades, but UN recommendations are not binding and investment in improving migration data has been minimal. There is an urgent need for a global action plan to boost data on migration to improve policy responses and improve the lives of migrants.

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