Migration forecasting is intended to provide informed guesses about future migration flows and trends. This is crucial information for policymakers to anticipate future challenges and adjust policies, design programmes and allocate resources. The term “forecast” is often used synonymously with “prediction” or “projection”, despite slight differences in meaning. Migration forecasts can be based on various and differing assumptions and results are prone to high uncertainty and errors because it is not possible to accurately predict the future.
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Migration forecasting is the attempt to predict future migration flows and trends using, traditionally, quantitative modelling methods. This approach statistically models future migration trends based on quantitative data from the past. This type of modelling is possible when rich numerical data are available, for example, on past inflows and outflows, policy changes, as well as various other migration factors and drivers.
The quantitative modelling approach, however, does not take into account factors that are unquantifiable and uncertain, yet relevant to migration. As such, a second approach that uses qualitative scenarios methods exists to predict future migration flows and trends.
The qualitative scenarios approach describes future migration developments in terms of narrative scenarios, based on a variety of information on migration factors and drivers. Qualitative techniques used in such futures studies are largely subjective, based on the opinion and judgment of experts. As such methods do not have to take into account statistical information about trends, it can be used when past data are limited, not comparable or infrequent. Still, it is possible to combine qualitative and quantitative information in forecasting, for example by using expert-based probabilistic methods, or – more recently – Bayesian statistical approaches, applied recently at the global level.
Migration forecasts vary in their predictions of future migration flows and trends. The United Nations Population Division predicts a drop in net migration levels between 2010 and 2020, and constant levels until 2050 (UN PD, 2015). According to the UN, in high-income countries, net migration is projected to account for 82 per cent of population growth. In most of these countries, the population size would decrease without future migration (UN DESA, 2015).
In terms of alternative scenarios for the whole world, researchers at the Vienna Institute of Demography project the total number of migrants globally over the next 50 years to remain almost constant (Sander et al., 2013). Migration scenarios developed by the Organization for Economic Cooperation and Development (OECD), among others, expect global migration to increase or at least stay constant due to population growth in low-income countries, coupled with labour market shortages and ageing populations in high-income countries (OECD, 2009).
Quantitative migration forecasts are often produced by National Statistical Offices and university research institutes and most often focus on a particular region or country. There are a few large providers of population projections at the global level that include projections of international migration:
- The United Nations Population Division of the Department of Economic and Social Affairs (UN DESA) has the longest record of production of global population estimates and projections until 2100, including international Migration assumptions. Since 1951, it has produced 24 rounds of its global population estimates and projections. To date, the latest version of its series of World Population Prospects (WPP) is the 2019 Revision. WPP currently covers 233 countries and territories, making it the geographically most complete dataset (UN DESA, 2019).
- The Wittgenstein Centre for Demography and Global Human Capital provides projections of net migration rates per country until the year 2100 based on different scenarios and assumptions (Wittgenstein Centre, 2017).
Other datasets have been made available for particular regions, for example, the European Union (EU)'s EUROPOP, produced by Eurostat, is the most recent edition covering the period between 2015 and 2080 (EUROPOP, 2015). These datasets from Eurostats provide information at national level across 29 European countries: for each EU-28 Member State and Norway.
Data sources for qualitative migration scenarios include:
- The Global Migration Futures project (IMI, 2017): This project uses systematic exercises with international migration experts and stakeholders combined with conventional social scientific research methods to examine potential future political, economic, social, technological and environmental changes at the global level and their consequences for migration.
- The Future of International Migration to OECD Countries report (2009): By analyzing different pull and push factors and constructing five different scenarios of migration in the future, this report examines the key determinants of global migration flows.
More recent approaches try to combine both quantitative forecasting based on numerical data with expert-based assumptions (Sander et al., 2013).Back to top
Data strengths & limitations
Various migration forecasts are available at the national, regional, and to a lesser degree, at the global level. On the pro side, migration forecasting is an exercise that allows stakeholders to systematically consider and prepare for likely future developments.
However, forecasting is notoriously difficult and unreliable (IOM, 2016). There are many reasons why migration forecasting is such a difficult task:
- Lack of uniform concepts and definitions for migration: For example, many countries define migration flows differently. In principle, migration involves relocating across an international boundary for a period of time, but the exact operationalization of this concept in practice varies.
- There are many—and unpredictable—drivers of migration: The diversity of motives behind migration flows and the emergence of new types of migration make it difficult to predict. (IOM GMDAC, 2016).
- Forecasts are based on different, imperfect and interacting assumptions: Migration forecasting relies on assumptions regarding demographic dynamics, the political, environmental and socioeconomic changes, as well as migration policies. The sheer number of push and pull factors (determinants) and drivers of mobility and immobility, all interacting with one another, makes a comprehensive explanation of migration processes anything but possible.
- Underlying data may be incomplete and not reliable: In many developing countries empirical evidence about past and current migration flows is almost entirely missing, and for a number of developed countries, data are also incomplete or unreliable (Buettner and Muenz, 2016).
|Raymer, J., and F. Wiilekens|
|2008||International migration in Europe: Data, models and estimates. John Wiley & Sons.|
|Buettner, T., R. Muenz|
|2016||Comparative Analysis of International Migration in Population Projections. KNOMAD WORKING PAPER 10|
|International Organization of Migration (IOM)|
|2016||Migration forecasting: Beyond the limits of uncertainty. Global Migration Data Analysis Centre, Data Briefing Series, Issue No. 6|
|2011||Forecasting International Migration in Europe: A Bayesian View. Springer|
|Sander, N., G. J. Abel, and F. Riosmena|
|2013||The Future of International Migration: Developing Expert-Based Assumptions for Global Population Projections. Vienna Institute of Demography 7/2013|
|Azose, J. and A. Reftery|
|2015||Bayesian Probabilistic Projection of International Migration, Demography 52(5): 1627-1650|