On a visit to Rio, my daughter took the favela tour, which included a visit to a slum school where children were working on computers. The slum also had gotten running water. Which helps kids more? Probably clean water, argues Timothy Ogen in Miller-McCune Online.

One Laptop per Child — an attempt to transform Third World education by distributing $100 laptops — is faltering, Ogden writes. But there are cheaper, more effective alternatives that make a real difference.

In the U.S., many programs to give laptops to students have been abandoned due to “high costs and no evidence of benefit,” writes Ogden. In the developing world, studies have shown few benefits to technology. In Romania, giving computers to poor families “had a negative effect on students’ grades and educational goals.” Giving computers, curriculum support and training to teachers in Colombia had “no impact on student outcomes.” A study in India found students did worse if they used computers during school hours but better if they used them after hours to drill on skills.

What does work? Deworming, writes Ogden.

Delivering deworming medication costs 50 cents per child per year in Kenya but yielded a 25 percent increase in school attendance; a similar program in India cost $4 per student per year and yielded a 20 percent attendance gain.

Nearly 40 years ago, a professor who’d taught in Africa told us about the curse of parasitic worms. Students had no energy to learn; workers tired easily.

Getting teachers to show up and teach also makes a big difference. Indian students did much better when “teachers were required to take date-stamped digital pictures of themselves with students each day in order to receive their pay.” Cost of each additional day of teacher attendance: $2.20.

Splitting classes into high and low performers helped both types of students in Kenya. Adding an other teacher was much cheaper than buying laptops.

In rural India, tutors improved the performance of low achievers at very low cost.

Because public schools are so bad in Third World countries (in part, because teachers don’t show up), poor families sacrifice to send their children to private schools with average fees of $3 a month, James Tooley, a British professor, has found.

Tooley estimates that more than 50 percent of urban slum-dwelling children, and nearly 25 percent of children in rural India, where per capita income is less than $2 a day, attend private school, even though public schools are nominally free.

. . . Cutting the cost of such schools in half via subsidies or scholarships, enabling even more parents to be able to afford to send their children (or to send additional children), would cost just $18 per child per year, on average.

Don’t fetishize technology — or anything else — warns Alexander Russo.

Keep It Simple, Smartie is a good slogan too.