Girls share books during their lessons at Undugu school in Nairobi, Kenya, Friday, June 29, 2007.

The number of African children enrolled in primary school increased from 56 percent in 1999 to 73 percent in 2007, according to figures from the United Nations Educational, Scientific and Cultural Organization.

While this improvement is encouraging, experts warn that Africa is still in the throws of a serious education crisis. About 61-million children, roughly half of the primary school-age population, “will reach their adolescent years without being able to read, write or perform basic numeracy tasks,” according to a recent report by the Brookings Center for Universal Education. In other words, children are going to school, but they aren't actually learning anything.

What is going on? Numerous studies document proximate causes, which include teacher absenteeism (18 percent in Senegal, 23 percent in Tanzania, 27 percent in Uganda) and neglect (when present, teachers are in class teaching about a quarter of the time).

However, the underlying cause however may be politics, writes Shanta Devarajan, World Bank chief economist, for Africa. "The fact is that public sector teachers welcome campaigns for universal primary enrollment. They imply more jobs for teachers, and enrollment is relatively easy to achieve, he noted on the World Bank blog Africa Can End Poverty. Increasing school enrollment is easy and politically popular.

Tensions arise, however, when it comes to campaigns that attempt to improve learning outcomes. Many teachers are simply not supportive of the goal, said Devarajan. "The reasons are two-fold," he explained. "First, learning outcomes are much harder to achieve. Secondly, if the campaign calls for learning outcomes regardless of where the children are enrolled, there may be a shift towards private schools — and fewer public-school teaching jobs."

Devarajan concludes that Africa's learning crisis will never be resolved unless countries commit exclusively to a universal learning goal. An example would be a goal for every child to know how to read, write and perform simple arithmetic by age 12.