PROMINSTAT Working Paper No. 04 - Possibilities and limitations of comparative quantitative research on international migration flows
In recent years international migration played increasingly important role in the shaping of the population dynamics in Europe, often becoming a more significant component of population change than the natural change. An increase in the stock of foreigners and considerable problems in their integration made societies and politicians look at migration flows carefully.
On the other hand, deficits of labour force on the global, regional and local labour markets, as well as the ageing of population made some entrepreneurs and policy makers look at migration as a cure to these problems. In consequence, the problem of migration became a topic of political and policy discussions, especially the question of immigration.
The developments outlined above have gradually led to an increased awareness, among researchers, planners, entrepreneurs, policy makers and politicians that there is a need for good quantitative migration flow data. For researchers, data are indispensable in a wide range of disciplines, such as demography, geography, sociology or economics, mostly to assess the developments and to make informed statements on their consequences and future developments. For planners and policy makers, they are needed to make operational decisions concerning implementation of infrastructural and social projects and programmes addressing migration-related needs as well as to provide sound population and labour market management. Politicians need data to shape migration policies.
Poorly defined, bad quality or otherwise inadequate migration data have an impact not only on official migration statistics but also on statistics of population stocks and in consequence, indirectly, demographic indicators such as fertility and mortality rates or economic performance indicators as, for example, GDP per capita.
In the study, we have presented a detailed analysis of the availability, reliability and comparability of data on international migration flows in 27 European countries (all EU Members States except Bulgaria and Romania, plus Norway and Switzerland). Our conclusion is that internationally comparative research on migration flows in Europe are currently generally not possible. The main problem is the comparability of data, in particular the differences in definitions and sources used in various countries and in the coverage of the statistics. These differences imply that comparing migration flows in various countries would be often like comparing pears and apples.
Researchers undertaking any international comparisons should carefully check the meaning of the available data and investigate different sources. Comparisons may only be attempted if the data from various countries measure the same phenomenon. If the data are not internationally comparable, any conclusions may be drawn only separately for each country, for the categories of migration flows measured in the given country.
Researchers trying to go more deeply than just total flows and interested in various characteristics of migrants encounter not only the comparability problem, but also the problem of the lack of data. Characteristics available in most of the countries are age, sex and country of citizenship of migrants. Information on previous or next residence is also often collected but is more problematic and may be missing. Information on the country of birth and marital status of migrants is often collected in the databases as well, but the relevant statistics (flows by country of birth or by marital status) are rarely prepared. Other important characteristics are frequently not available.
Most readily available data concerning migration flows are macro-data. The main source of these data are administrative registers, with no or a limited access to the micro-data for the researchers. As a consequence, researchers that want to go beyond the usually published statistics face the necessity of organising dedicated surveys.
Clearly, improvement of international migration statistics requires international cooperation. In Europe, considerable progress is envisaged when the data prepared according to the EU Regulation on international migration statistics begin to be published. It should be noted that the last years brought in an evident improvement in migration statistics on international migration flows in some countries. In our opinion, this is a direct consequence of the preparations for the EU Regulation. Notably, Bulgaria and Greece started to provide flow data to Eurostat (Greece only for immigration), and Estonia will probably follow as its quality of data significantly improved and it began to publish statistics on international migration flows in 2009. Slovenia has changed its definitions and adopted the one year duration of stay rule in migration statistics. However, the scope for further improvement is still wide, both in the field of the international comparability of data, as well as in data availability.
If we want to facilitate interdisciplinary research, we need complex multidimensional data. In addition to the statistics on flows specified in the EU Regulation, statistics describing socio-economic characteristics of migrants are needed. The most sought-after variables include reason of migration/purpose of stay, level/years of schooling, profession, employment status and salaries in the origin and destination country, source of household‟s income, migration history. The extension of the data characterising those who migrated to include both direct questions about reasons of their migration and their economic and labour market characteristics would allow to replace quite imprecise proxy variables with actual explanatory variables. No doubt, this would be a tricky data collection. Perhaps a sensible solution is to create a pan-European longitudinal data collection focused on migration.
Statistical offices should investigate the possibility of linking existing administrative data sources to retrieve missing information. Researchers need better access to the anonymised micro-data from the administrative sources. As far as international cooperation is concerned, wider exchange of information between receiving and sending countries may be helpful.