Frontiers Openness and the Optimal Migration Duration

Raising barriers to entry is a common policy used to limit immigration. The implicit assumption is that migrations are permanent. However, a growing literature has begun to study migrations as a temporary decision in a dynamic framework. In this light, policies aimed to limit inflows overlook their feedback on outflows. In what follows, we argue that both theory and historical evidence show that temporary migrations are the rule rather than the exception, and that there exists a trade-off between frontier closure and migration duration. As a consequence, a strict regulation of entries may not be optimal, because it decreases both inflows and outflows, and the net result may be an increase of the foreign population in the host country. Differently from most of the existing literature, and according to historical evidence, we argue that there is no reason to consider the return decision as permanent. Using both a life-cycle and an infinite-horizon model, we find that expectations on a possible return in the host country are indeed the key mechanism that allows frontier closure to backfire on migration duration. Moreover, we show that a policy only focused on frontier control overlooks the possible benefits of international co-operation.