This paper proposes procedures for the study of migration across national boundaries within the European Union. The specific issues of concern are: (1) the extent to which existing social surveys may be used for the purpose; and (2) new and alternative arrangements to study the phenomenon in-depth. The scope of information to be collected may be defined in the form of a hierarchical set of modules: (1) a core module to identify the proportion of immigrants in the population and obtain information on basic characteristics; (2) a short module to obtain information on motivations and circumstances of migrants; and (3) a long module comprising a more detailed sets of questions aimed at recent immigrants.

Three types of instruments or designs are described for the purpose. (1) Regular household surveys, based on existing harmonised EU-level social surveys. (2) Special sampling procedures extending conventional sampling using link-tracing designs. The populations of movers across EU national boundaries have certain characteristics which makes them 'elusive' to the sampling process by virtue of their characteristics (small population size, patchy concentrations, great heterogeneity, changing identity and profile, reclusive character) or of the lack of suitable sampling frames. Beyond conventional sampling procedures, we may use link-tracing designs where elements initially selected into the sample lead to the inclusion of other elements on the basis of some suitably defined links between the population elements. Examples are multiplicity or network sampling, chain-referral methods (snowball and respondent-driven sampling), random-walk designs, adaptive cluster sampling, capture-recapture sampling, and also some non-probability selection methods. (3) Many elusive populations tend to congregate in particular places or territorial sites, and such 'centres of congregation' may be used as alternatives to household-based surveys.

Keywords: International migration; European Union; Household surveys; Special sampling procedures

Biography: Vijay VERMA has wide experience in survey design and analysis internationally, including on European social surveys. He began his international career at the World Fertility Survey in London, and has been a Technical Adviser at United Nations Statistical Office in New York, Director of Research Centre of International Statistical Institute in The Hague, Research Professor at University of Essex, and currently is Visiting Professor to University of Siena. He also has been an independent statistical consultant to international organisations for many years, and has provided training and technical assistance in nearly 50 developing and transition countries worldwide, and has been a consultant to Eurostat for twenty years.