Tina Rosenberg has an excellent piece on private schooling in developing countries at the NYTimes blog:
In the United States, private school is generally a privilege of the rich. But in poorer nations, particularly in Africa and South Asia, families of all social classes send their children to private school….
BRAC used to be an acronym for Bangladesh Rural Advancement Committee, but now the letters stand alone. It was founded in 1972 to provide relief after Bangladesh’s war of liberation. Although you’ve probably never heard of it, BRAC is the largest nongovernmental organization in the world, with some 100,000 employees, and it services reach 110 million people.
…And since 1985, it has run schools… BRAC has more than 1.25 million children in its schools in Bangladesh and six other countries, and it is expanding.
BRAC students, in fact, do better than their public-school counterparts….BRAC students are more likely to complete fifth grade — in 2004, 94 percent did, as opposed to 67 percent of public school students. (The BRAC number is now about 99 percent.) On government tests, BRAC students do about 10 percent better than public school students — impressive, given that their population is the most marginalized. (emphasis added).
In my own work on private schools in India I also found suggestive evidence that private schools–mostly very small, urban slum schools–produced better outcomes than their public counterparts (paper (pdf), video).