According to wikipedia,

A brain drain or human capital flight is an emigration of trained and talented individuals (“human capital“) to other nations or jurisdictions, due to conflicts, lack of opportunity, or health hazards where they are living.

And, as is clear from this definition, brain drain is a word with a bad connotation. So, it is no wonder that we hear our politicians, statesmen and intellectuals often mourning brain drain.

For example, here is the President of India, Dr. Abdul Kalam on reversing brain drain:

President A P J Abdul Kalam today announced the government would encourage a ”reverse brain drain” to attract some of the brightest and talented children of India and ensure their return to their motherland.

Addressing a joint sitting of Parliament, he appealed to the overseas Indians to engage more actively in India’s development.

The latest issue of Nature brings some good news; in an editorial titled In praise of the “brain drain”,  there are some interesting observations:

There is a clear correlation between emigration and the state of the public health care system, but not the one you might expect. The higher the proportion of an African nation’s nurses and doctors who have moved abroad, the better shape its health care is likely to be in.

These observations are based on a report which is available here. So, the article concludes on a positive note, namely that emigration is a not a zero sum game — very encouraging news indeed!