Powered in part by the non-profit online education resource Khan Academy, the Los Altos School District in California is expanding the “blended-learning” pilot it ran last year, writes authors Clayton M. Christensen and Michael B. Horn.

The district’s fifth, sixth and seventh graders’ math classes are a hybrid of normal and online learning. With teachers coaching the students to keep up with their math goals and help them apply the math concepts in small-group and class-wide projects.

Online learning is also grabbing the imagination of the capital. D.C. Schools Chancellor Kaya Henderson has expressed interest in bringing one of the more successful blended-learning school models, Rocketship Education, to the district, as reported by Bill Turque in the Washington Post.

For the first time in roughly a century—since the transition from the one-room schoolhouse to the classroom- and age-based school—a dramatic change in the basic way we structure our educational system is afoot, write Christensen and Horn.

“Online learning is on the rise in the nation’s public schools. In the year 2000, roughly 45,000 K-12 students took an online course. In 2010, roughly 4 million did, according to Ambient Insight. And, according to our projections, 50 percent of all high school courses will be taken online by 2019—the vast majority of them in blended-learning school environments with teachers, which will fundamentally move learning beyond the four walls and traditional arrangement of today’s all-too-familiar classroom.”

Entrepreneurs and investors are looking to fashion the future by creating new learning and schooling models and liberating students and teachers. Others are working to create adaptive-learning platforms.

Just as Netflix or Amazon can help recommend the right movies or books based on your personal preferences, these platforms hope to match the right learning experiences for a student at any given time based on a variety of learning heuristics, writes Christensen and Horn.

However, policymakers and regulators still want important questions answered:

“If they do not put in place the rules and structures that both leverage and incentivize the innovations in development, then there is no guarantee that the public education system will be transformed into a student-centric one.”

To do this, Christensen and Horn suggest that policymakers and others must move beyond the old input-based metrics used to micro-manage how people in the existing public-education system work and instead embrace outcomes-based regulations that reward individual student learning gains and liberate educators on the ground to figure out the best way to achieve those gains.

Districts defined by geographic boundaries and brick-and-mortar buildings. Among the challenges of online education is dealing with what it means to be publicly financed in a digital education world, where much of the curriculum and even employees can come from profit-making companies. This means online education threatens many concepts that are fundamental to the identity of public education, writes Morgan Smith at the New York Times.

Some educators want more evidence that online instruction works, and they are skeptical of such enthusiastic private-sector involvement. Gene V. Glass, a senior researcher at the University of Colorado’s National Education Policy Center, who will release a study on virtual education this fall, questions the findings of a 2009 United States Department of Education analysis that found online learning could lead to superior results. In the five studies that were collected at the kindergarten-through-12th-grade level, he said, the students who took courses online had more time to study — or they also had face-to-face instruction, writes Smith.

Mr. Glass also said the same “five or six” companies produce most of the curriculum that students use in virtual courses. That is a problem, he said, because “they are responsible to their shareholders, not to the kids or anyone else. They are in it for the money.”