مهاجرت، انباشت سرمایه انسانی و توسعه اقتصادی

We study how the possibility of migration changes the composition of human capital in sending countries, and how this affects development. In our model, growth is driven by productivity growth, which occurs via imitation or innovation. Both activities use the same types of skilled labour as input, albeit with different intensities. Heterogenous agents accumulate skills in response to economic incentives. Migration distorts these incentives, and the accumulation of human capital. This slows down, or even hinders, economic development. The effect is stronger, the farther away the country is from the technological frontier.

Classical theoretical studies on the Brain Drain hold that migration of skilled workers is beneficial for destination countries and harmful for source ones.1Bhagwati and Hamada (1974), Kwok and Leland (1982), Galor and Tsiddon (1997), and Miyagiwa (1991), for example, all point at the potential negative effect of the outflow of human capital on source countries. These predictions, however, are at odds with the experience of some sending countries that grew faster than relatively more closed ones. Examples include Japan, South Korea, Taiwan and Singapore as opposed to Bangladesh, India and Indonesia.2 Recently, the literature has focused on the potential for a Beneficial Brain Drain, a Brain Gain (BG). The central proposition of studies such as Mountford (1997), Stark et al., 1997 and Stark et al., 1998 and Vidal (1998), and Beine et al. (2001) is that the possibility of emigration reinforces the incentives to accumulate skills, and that source countries actually increase their stock of human capital as possibilities to work abroad increase. Empirical work on the effects of skilled migration on source countries has provided mixed results. Recently Beine et al. (2008) have shown that the net effect of the brain drain can be either positive or negative, and that the BG hypothesis is supported only for a small number of countries. The authors conclude pointing out the necessity of a better understanding of the circumstances and factors favouring the occurrence of a detrimental brain drain. This paper focuses on the role of the composition of human capital in fostering productivity growth and economic development. Our study is based on the well established literature that points at productivity growth as the key engine driving innovation and thus economic development (see Jones, 2005, for a discussion). The arguments we present are additionally motivated by the recent literature discussing the determinants of innovative societies (e.g. Feinstein, 2006). The literature on the BG implicitly assumes that all human capital is equally useful to the sending country, irrespectively of its stage of development. A long literature dating back to Becker (1964), instead, recognizes the different roles played by different types of human capital. In a development context, both Durlauf and Johnson (1997) and Krueger and Lindahl (2001), for example, provide evidence as to the heterogenous effects of education on growth across countries with different levels of development. Recent investigations have highlighted complementarities between different types of human capital in the innovation process. Mokyr (2005), speaking of the industrial revolution, argues that it had less to do with technological breakthroughs, and more with the intellectual climate linking creative efforts to economic rewards. Sustained growth became possible thanks to the systematic transformation of inventions into commercially lucrative technologies. In a modern context, Yusuf (2007, page 3) recognizes that “many forms of creativity can be valuable, [but] the economic yardstick favours creativity which leads […] to commercial results”. Thus the degree of (economic) success of a society depends on its ability to promote the sustained conversion of inventions into innovations; this ability “is a function of organizational capabilities and the coordinated use of multiple skills—managerial, financial, marketing and legal”.3 In other terms, scientific knowledge and technical skills, while necessary, are not sufficient to the emergence of innovative societies. Instead, the more advanced a society, the more fundamental the need for a full range of competencies and skills. Following up on this discussion, we assume that imitating available techniques is an easier task than bona fide innovation. Thus, in the early stages of development, when the main task is to copy and adapt available technologies, a specialization in technical skills may be helpful. At later stages, however, the development of truly innovative techniques requires a broader range of skills: technical, financial, managerial, legal and political. Thus, we assume that improvements in productivity depend on the composition of human capital in each country, and on the distance from the technological frontier. We recognize that skill accumulation is influenced by the prospects of migration. The International Organization for Migration (IOM, 2003) recently claimed that “prospects of working abroad have increased the expected return to additional years of education, and led many people to invest in more schooling, especially in occupations in high demand overseas.” To capture this effect, we extend the model of Vandenbussche et al. (2006), making skills accumulation endogenous, and study the interactions between human capital accumulation, labour market outcomes, and migration possibilities, and their implications for the process of development. Our results show that migration distorts the agents' incentives to accumulate the most appropriate skills for their country of origin; this reduces the growth rate of the source economy. We identify (plausible) circumstances under which this process leads to development traps, i.e. situations where convergence stops short of the technological frontier. The model's policy implications provide a rationalization of policies implemented by successful East-Asian economies, where Governments invested in specific types of tertiary education with an eye to the interests of local employers. Our conclusions are also consistent with the recent shift from interventionism to laissez-faire in these countries: when convergence has been achieved, direct interventions become redundant, and market mechanisms regain center stage.

The debate on the economic effects of the brain drain on developing countries has yet to reach univocal conclusions in many respects. This paper contributes to the understanding of this phenomenon showing that the possibility of migration, blurring the borders between economic systems at different levels of development, reduces economic growth. We show that migration distorts price signals and induces changes in the accumulation of human capital. This ultimately proves detrimental for developing countries. Hence, the brain drain lowers the pace of development for lagging countries, and may well lead to development traps. From the normative point of view, we show that Governments can play an important role in encouraging the acquisition of those skills that are most needed domestically. However, since the distortionary impact of the migration prospects decline with the proximity to the frontier, the Government's support in favor of certain skills ought to taper off as the development process proceeds. We find that these implications of our model conform with the experience of successful East-Asian economies.