While developed countries are angst-ridden over mostly illegal immigration by unskilled workers from developing countries, a different set of concerns has surfaced in Africa, in particular, over the legal outflow of skilled and highly skilled people to developed countries. This outflow is supposedly a new and damaging brain drain with rich countries actively luring away needed skills from poor countries.

This fear is misplaced. At the outset, we have to distinguish between need and demand. Yes, many African countries need skills. But they are unable to absorb them, owing to several factors associated with economic backwardness.

In India in the 1950s and 1960s, working conditions were deplorable. Bureaucrats decided whether we could go abroad for conferences. Heads of departments carried inordinate power. So, no surprise, many of us left.

Keeping people at home is easier said than done. In many poor countries, except those like India and South Korea, which have now developed superb educational institutions, the brightest citizens receive their education abroad. The challenge, then, is to prevent them from staying there and settling down.

But, in any event, emigration restrictions today would violate a human right enshrined in current international treaties. But would immigration restrictions work instead, as proposed by some developed country organizations that worry about the brain drain?

Here, human rights concerns pose serious difficulties. Could we really say to a Ghanaian doctor that she must return to her country while an immigrant Russian doctor is allowed to settle down and start a new life? This is likely to run afoul of anti-discrimination principles and constitutional provisions in countries like the United States.

The proper response to the outflow of skilled manpower from poor countries, especially those in Africa, is to be found in a different direction. Given that outflows of skilled workers cannot be restricted — and, indeed, should not be — we must devise institutional mechanisms to work with it. This means adopting a diaspora model, which implies four policy proposals.

First, stop crying over the fact that the diaspora is not returning home. Instead, nurture the loyalty of professionals settling abroad, so that they assist their home countries in a variety of ways. Thus, they may be offered voting rights. Restrictions on investment and land purchases can be dropped. Immigration experts such as myself have proposed since the 1970s that schemes be developed to enable the academic diaspora to run workshops aimed at bringing teachers up to the best international standards.

Second, while the diaspora should be integrated through more rights, its members also ought to accept obligations that put them on an equal footing with those who remain behind. I suggested in the 1970s that a tax be levied on citizens abroad. Known as the "Bhagwati Tax," it is of course "the American way." U.S. citizens and permanent residents abroad, like those at home, must pay federal taxes.

Third, because skills are necessary for nearly all activities in most of Africa, here and now, we need to organize ways to supply such skills to these countries. I have long argued that because many in rich countries are retiring while still in sound health and because altruism increases with age, we could organize a Gray Peace Corps of senior citizens to share their skills in countries whose own trained professionals prefer to settle abroad.

Finally, foreign aid should be used to expand training massively for Africans in all the essential fields in rich countries like the United States, Britain, France and the Netherlands. They would add to the diaspora, while the Gray Peace Corps would help to fill current needs. When development has taken off, and conditions have improved sufficiently to attract people back to their homelands, the hugely increased diaspora would indeed return, as they have done in India, South Korea and China.

Together, these policies would benefit Africa both immediately and in the long run. Sentimental handwringing over the brain drain and foolish attempts at restricting people's mobility will not.