A child in Mexico City earns his wage cleaning windshields. Photo: Beto (Kuh) (Flickr)

So far, more than 4 million Mexican families have benefited from a government program aimed at combating some of the country’s toughest problems: poverty, illiteracy and poor health.

Oportunidades, which began in 2002, takes the innovative approach of paying these families to go to school, eat well and stay healthy. Eight years later, the concept is gaining international momentum.

The program is based on a “conditional-cash” idea, whereby eligible adults are given money for achieving specific goals, including regular medical checkups, taking classes on healthier eating habits, and making sure their children are enrolled in school.

Santiago Levy, a social economist and one of the men credited with implementing the “conditional-cash” approach in Mexico, recently spoke about Oportunitidades with PBS. Levy said that he wanted to focus on lasting ways to bring people out of poverty.

These families were trapped in … some kind of an intergenerational mechanism, by which parents were poor, children were poor, and the next generation were also poor. The kids were so poor, they had to be picking coffee in the fields, and they couldn't go to school ... [Through Oportunidades,] what you are saying is, your kid will be equally valuable to you if he's in the school, as opposed if he is in the street begging for money.

One of the most intriguing aspects of Oportunidades is its rigorous evaluation process. The program uses an outside firm to review every aspect of its impact, and so far the results have been convincing. In some affected regions, school enrollment is up 20 percent for girls and 10 percent for boys, according to a World Bank report.

The unique evaluation process has also offered Oportunidades a certain degree of credibility and international recognition. PBS reports that more than 30 counties — many in South America and Southeast Asia — are developing their own "conditional cash" programs.