Today the Brookings Institution celebrated the new Mo Ibrahim Prize for good governance in Africa. Ibrahim has hit on a fascinating incentive for African leaders who consistently work to improve governance -- and voluntarily step down from power (leaders in office are not eligible).

It's hard to argue with the press release: "Joaquim Chissano [former president of Mozambique] wins the largest prize in the world." A brief description from Brookings:

Recognizing that improving governance takes political leadership, Mo Ibrahim, the founder of Celtel, created the Prize for Achievement in African Leadership to be awarded to a former African head of state or government who has demonstrated excellence in African leadership. Consisting of a $5 million award to be paid out over 10 years and a $200,000 annual stipend after that, the prize has grabbed the attention of the governance community for its vision and initiative. The winner will be chosen based on a new African governance quality index designed by Robert Rotberg of Harvard University.

Doubtless, many African leaders could take in more than this sum by situating contracts and government revenues to their advantage. But Ibrahim promises both the aplomb of the international community and a tidy sum for doing the right thing and leaving it well enough alone once a positive impact has been made. As commentators at Brookings noted, equally important will be the linear data that accrues from the index as the prize is reassessed every year.

And let's hope that the Mo Ibrahim Foundation can avoid "World Bank disease" -- awarding only prizes that are well-deserved. A year or two without prizes might be just as powerful an instrument for good governance.