Is it time to phase out UNDESA’s regional criterion of development?

International migration to developing countries has attracted increasing attention because of its growing volume in absolute terms and its potential contribution to development. However, conclusions about what is happening in these countries depend crucially on the way migration and development are measured and analysed. This article shows that whether migrant stocks appear to be increasing or decreasing in developing countries depends on three factors: whether a regional or an economic criterion of “development” is used, whether volume is expressed in absolute numbers or as a percentage of total population, and whether the data include refugees and asylum seekers. The policy implications of these findings, which – due to the shortcomings of available data – can only be regarded as provisional, are then discussed. Better quality migration data and analysis informed by the limitations of the data are needed to provide a sound evidence base for current debates about migration policy.