Migration

Although the most common explanations are those focusing on the economic dimensions, a general survey of the literature on demographic mobility reveals numerous economic, sociological, and demographic attempts to explain the initiation of internal and international migration. Migration is seen as a response to both endogenous and exogenous variables. These variables are, in sum, the overall effects of sociocultural, economic, political, and psychological conditions on the migrant. The decision to migrate is thus a response to one or many of the variables and the location of such variables. The sociologist describes migration in relation to the nature and magnitude of its social and cultural dimensions, the destination, and the sending area. The economist, on the other hand, reflects on the occupational and employment status, pressure of demand and supply, and relationships among wage, income, and price levels. Demographic explanations relate all the variables to the prospect of measurement and control of migration and its effect on growth and development.

Given Africa's cultural, linguistic, and economic variegations, and its vast country-to-country differences, a systematic analysis of any aspect of its social behavior can be a difficult enterprise. Analysis of its migration behavior is no less challenging. When applied to the African situation, accepted theories of migration reveal the need for the development of models that distinguish between developed and developing countries. Indeed, a number of explanatory models have been developed in the literature seeking to explain internal and international migration of labor in undeveloped countries. Three of these are especially suited to the African situation. These are the Todaro's, Mabogunje's, and Byerlee's models.

Todaro's model is a modification of the neoclassical economic (human capital) theory of migration. The theory posits that migration is the consequence of individual cost-benefit calculation. Todaro proceeds by affirming that migration is based on rational economic calculations and argues that the decision of the individual to migrate is usually a response to rural-urban differentials in expected rather than actual income earnings. This model assumes that the potential migrant selects a location that maximizes expected gains from migration. This was the first explanatory attempt emphasizing that potential migrants should base the decision to move on rational calculation of differences in expected earnings.

Mabogunje's model constitutes the second approach at explaining migration in Africa. The model is a creative adaptation of the world systems model in which Mabogunje asserts that rural-urban migration in Africa is controlled by systematic interrelationships of rural-urban control systems, rural-urban adjustment mechanisms, and the positive or negative flow of information about migration. The model identifies the push and the pull sides of migration. Local economic conditions that affect the pool of migrants constitute the push side. The size of this pool is affected by social practices, customs, community organization, and inheritance laws in the sending community. Wage rates and job opportunities emanating from the urban system constitute the pull side of migration, and these determine whether individuals in the pool of potential migrants would migrate.

In a modification of the human capital approach, Byerlee adopts a cost-benefit economic model in which he considers migration as the outcome of a cost-return calculation. Byerlee posits that the decision to migrate will be made when the perceived returns of migration exceed the perceived costs. The model goes beyond the conventional cost-return analysis of the human capital approach as it includes elements of the social system. It also explicitly identifies determinants of rural and urban incomes and introduces risks and other psychic costs into the migration decision-making process.

All three approaches have made significant contributions to a conceptual understanding of the migration process in Africa. Todaro's model provides a good explanation for labor migration in Africa, as it recognizes the unequal and uneven distribution of economic and social development between regions of the same country and among countries as a primary determinant of migration. The strength of Mabogunje's approach lies in its macrosystem emphasis, given its recognition of the economic, cultural, and social relationships between rural and urban areas. Mabogunje's model is particularly helpful in understanding the impact of family and community organization on migration. Byerlee's conceptualization of the motivation for migration in Africa has also contributed significantly to a conceptual understanding of migration in the region.

Despite their theoretical contributions, all three models fail to deal adequately with several elements of migration, including forced migration. With regard to historically more recent migration patterns, the models fail to deal with non-wage urban income, which accounts for an increasing proportion of urban employment.

One element of migration that has assumed increasing importance in recent years is the large-scale international migration of skilled persons from Africa to relatively more developed regions of the world. Attempts to provide explanatory models for understanding the motivation for this phenomenon confirm that the behavior of the so-called highly trained migrants, including scientists, engineers, artists, and intellectuals, is fundamentally determined by the same kind of motivations and market forces as those of less highly trained migrants. However, interpretations of the effect of the migration of highly skilled workers on the developing sending countries differ. Most economists are agreed that although some degree of mobility is necessary if developing countries are to integrate into the global economy, large-scale losses of skilled workers are detrimental to developing countries and pose the threat of a brain drain.

Neoclassical models of economic development hold that brain drain has adverse effects on the development of the sending country, slowing down the GDP growth rates and adversely affecting those who remain. Consequently, poverty and inequality are likely to increase. More recent economic theory—the endogenous growth theory—also predicts that emigration of highly skilled workers reduces economic growth rates. In contradistinction, another theoretical variant holds that at some optimal level of emigration (greater than none but not too much), sending countries actually benefit. It is argued that the possibility of emigrating to higher-wage countries may stimulate individuals to pursue higher education in anticipation of migrating to secure, better-paid work abroad. The consequence is the development of a large pool of better-trained human capital in the sending country. The implication is that there may be an "optimal level of emigration" or a "beneficial brain drain." Empirical analysis offers some support for the various theoretical expectations.