The thesis develops analytical tools able to shade light on the changing dynamics migration is experiencing and to evaluate how much confidence states should put on migration to deal with their demographic and fiscal challenges. The analysis, primarily based on Swiss data, is mainly divided in two parts. First, the role of countries interconnections in shaping migration trajectories is taken into consideration through spatial econometric models. Second, a new forecast method, which frame a semi parametric model within the Bayesian paradigm, is elaborated. The latter is further employed to predict the challenges the Swiss pension system is going to face in the next decades.