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"I like to think of education as giving people superpowers." With this metaphor, Coursera co-founder Andrew Ng summed up the purpose of MOOCs, or massive open online courses, at The Atlantic's Silicon Valley Summit on Monday: They're designed to help people gain discrete skills like coding or algebra or French. Education watchers have wondered how MOOCs will affect traditional classroom experiences from the elementary school to the university, and some have even argued that online education will fundamentally change the way students of all ages learn.

But according to entrepreneurs working in this space, MOOCs were never meant to stand in for regular classrooms. "To make to make this look like a silver bullet somehow—this was never meant to replace schools," said Sal Khan, the creator of Khan Academy. Both Khan and Ng described their products as educational supplements: Online courses help to fill a "skills gap" for people who are looking to get jobs in a certain industry or transition to a new career. But if someone is "debating between attending Johns Hopkins or taking free Coursera courses—for God's sake, go to Johns Hopkins," Ng said.

This may seems surprising for the founder of an online higher education start-up, but he and Khan gave a few reasons why traditional classrooms are more valuable than online classes. First, access is an issue: For lower-income students who can't get on broadband internet, online classes aren't of much use. During an interview with Khan and David Cohen, the Executive Vice President of Comcast Corporation, the two announced a new, multi-million dollar partnership to expand broadband access. But Ng sees this as a problem that's perhaps too big for one company to solve. "We're working with a few NGOs that are using Coursera as an excuse to prod local governments to improve access to broadband," he said, but this is one issue where they might be "too small of an organization" to make big changes in the near future.

But the most compelling reason why MOOCs fall short was this: "One thing that Coursera doesn't do well is teach non-cognitive skills," Ng said. "There are studies that suggest that 80 percent of your income are due to non-cognitive skills: teamwork, ethics, the ability to regulate anxiety. It's an open question whether Coursera can develop technology to teach non-cognitive skills. By contrast, universities do a much better job."

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