Sir

Your Editorial “In praise of the 'brain drain' ” (Nature 446, 231; doi:10.1038/446231a 2007) is, in my opinion, misleading in its representation of the issue and in its attempt to justify phenomena that are debilitating for the education and training of professionals in the developing world.

The effects of these phenomena on countries differ, depending on the extent of a country's development. Developed countries, on the whole, have large numbers of scientists and healthcare and other professionals in their populations, whereas developing countries may have just a handful. A major obligation of any government to its population is to pursue and implement policies that increase numbers of these key professionals to a desirably stable level, or — where they are already approaching stability — to maintain them at those levels. This responsibility on governments is independent of international opinion and is the reason why South Africa may decide to penalize individuals who leave the country after having been trained at the state's expense, or rebuke companies that facilitate the mass emigration of its professionals.

The gains from money sent back home, or from some expatriates returning to their native countries much later in their careers, may be of some benefit to those countries. But it is difficult to imagine how this could be more useful than doctors, nurses, teachers or lecturers staying in places where such people are seriously lacking.

You mention the correlation of higher emigration rates with better public healthcare systems, but a correlation is not a causal link. What else would we expect when the countries that 'drain the brains' have the power to pick and choose? When migration occurs between countries that have no large disparity in their development levels, the exchange is more likely to be mutually beneficial.

Given all this, I believe that there is nothing to praise about the brain drain when it occurs en masse from the developing countries into richer, more developed ones with dramatically more power.