Problems and Prospects
OECD Statistics brief n°9
Since the end of the 1990s, issues related to international migration have received increasing attention from policy-makers. This reﬂects, among other reasons, the increasing international movements that have taken place following the fall of the Iron Curtain and the growing globalisation of economic activity. Despite these increased movements and the heightened policy interest in this area, however, the quality and comparability of international data on migration have scarcely kept pace.
In particular, data that are generally available on international migration ﬂows do not provide a clear idea of the relative scale of movements across countries. The lack of comparability of international migration statistics is well known. It was with this in mind that the revision of the UN recommendations on international migration statistics (UN 1998) was undertaken in the mid 1990s, little progress having been achieved in harmonisation over the previous twenty years. Still, despite the rather pragmatic approach adopted for the 1998 revision, progress in improving the comparability of the statistics of migration ﬂows since then remains limited.
Why is it so difﬁcult to get the international picture right with respect to the extent of migration ﬂows? This Brief, which deals only with legal migration, as measured in the statistics of the receiving countries, explains the reasons and proposes some practical steps that could be taken to improve the situation.
The comparability of International Migration Statistics, Problems and Prospects