Population growth in European countries -as in any region- depends on both natural increase (the difference between births and deaths) and, to a large extent, on migration flows, i.e. the net outcome of residents leaving and people arriving, whether from within Europe or from outside. It is therefore extremely important to measure these flows accurately and, since the aim is to control them, to try to anticipate or at least understand the factors that may be driving or restraining them.
Unfortunately, according to Michel Poulain and Anne Herm, our knowledge of the flows within the European Union and of immigration from other countries is remarkably hazy -even though accurate knowledge is an obvious prerequisite for any ultimate agreement on a common migration policy- because the methods used for measuring flows are not altogether satisfactory and differ from country to country. For example, the authors point out, the estimates of the number of Italian immigrants in Belgium differ widely depending on which country's statistics you use.
Michel Poulain and Anne Herm present a sometimes surprising description of the methods used to measure international mobility, stressing the practical problems, the uncertainties surrounding the figures currently collected, indeed the real oddities that can occur.
In the second section, while bearing in mind the difficulties with the available statistics, the authors present an overview of the main trends within the European Union, focusing first on the size of the foreign populations in each of the member states and then on the special features of migration flows into Europe from outside.
While the growth of population flows within Europe augur well for greater European unity, the authors nevertheless conclude that there is an urgent need for more reliable data on international migration and, furthermore, this will be achieved only if there is a clear policy for the EU as a whole. Unfortunately, in this area even more than others, there is a regrettable tendency among the member states to shy away from the problem, doubtless for fear that the truth might be too disturbing.