Bill Gates and Mark Zuckerberg are backing a controversial education program in East Africa

It involves each student learning at his or her own pace, generally through the aid of technology, and it's beloved by tech billionaires like Bill Gates and Mark Zuckerberg.

But both Gates and Zuckerberg, in addition to other big names in Silicon Valley, also back an education model that is taking the opposite approach: pursuing learning gains with curricula standardized to each particular country.

Bridge International Academies, the subject of a recent New York Times Magazine piece, operates in hundreds of schools around Kenya and Uganda, with dozens more of its low-cost schools scattered through Nigeria, India, and most recently Liberia.

Though it operates with the mission of providing high-quality, low-cost education for all, Bridge has drawn criticism from some education experts and teachers unions for the model it uses to make good on that mission.

Bridge schools employ local teachers to use digital, pre-written lesson plans that get distributed across the company's international web of instructors. The percentage of teachers that must be certified varies by country, a Bridge spokesperson said. In Kenya, 30% must be certified. The spokesperson said 51% of their teachers meet that mark.

All Bridge students in a given country receive the same education at the same time — something personalized learning advocates generally shun as inefficient or, worse, ineffective.

By 2015, Bridge had raised $100 million, the Wall Street Journal reported. The money came in part from Gates and the Chan Zuckerberg Initiative, a company formed by Zuckerberg and his wife Priscilla Chan to give away 99% of their Facebook shares in order to advance science and education. In addition, the Omidyar Network, the World Bank, venture capital firms, and the hedge fund Pershing Square have jumped onboard.

But even Gates, a vocal advocate for uplifting those in the developing world, has said the old-school model of education doesn't always cut it.

The personalized learning philosophy underpinned special-education when it began more than 40 years ago, and it continues to work its way through in public schools around the US. Zuckerberg, too, has endorsed personalized learning time and again as the superior approach to instruction.

The fact Gates and Zuckerberg support Bridge financially likely reflects their primary goal of lifting the poor out of poverty. Smaller details about the specific style are perhaps immaterial if the data show the method is working. Bridge has data to back it up.

Correction: This article has been updated to more accurately reflect how many teachers are certified to teach in Bridge schools.