Gupta and Dal Poz [1], in a cross-country comparison including six countries, highlight the ‘ dual employment ’ (i.e. when the employee holds more than one position in different locations) as a factor which may represent a signal of unsatisfactory salaries. Dräger et al. [8] present a cross-country comparison of health workers ’ wages (i.e. physicians and professional nurses) for 42 countries, where data are available from the OWW database (i.e. International Labour Organization October Inquiry and Occupational Wages around the World), showing huge differences in average yearly wages earned by physicians and nurses between developed countries (USA being the highest) and the same professionals in poor countries. As the wage differentials have been proven to be so large between destination and source countries, Vujicic et al. [9] suggest that non-financial incentives may be more effective in order to retain health workers in their countries.