Quels gains peut-on espérer d’une libéralisation de la migration ?

As the TTIP negotiations with the US keep going, Europe toughens its immigration policy. Constraints imposed on the mobility of workers are estimated to cost up to several hundreds of billions of euros, a huge number compared with the potential gains expected from the TTIP. The aim of this paper is to review the studies that have quantified the gains from liberalizing migration and to discuss their underlying assumptions and mechanisms. If one assumes that liberalizing migration leads to a convergence of wages, the world production could increase by 50 to 150%, according to the first studies on the issue. Meanwhile more recent work which accounts for migratory preferences is less optimistic and shows that the volume of potential additional migrants has likely been overestimated. Still, the gains from easing migration restrictions are considerable, in particular if externalities, such as incentives for education, are accounted for.