Legal migration and illegal migration: the effectiveness of qualitative and quantitative restriction policies

摘要

By considering the optimal behaviour of illegal migrants who must confront the vari- ous enforcement techniques adopted by the host country, we show that an increase in penalties, in travel cost, or in the possibility of detection, would be effective in the 'qualitative' objective but not in the 'quantitative' objective. Moreover, when a host country starts accepting skilled legal migrants, if the required skill level is relatively low and the possibility of detection is sufficiently high, an increase in penalties will be effective in both objectives.