Some 700,000 K-12 students studied online last year, and nearly two out of three school districts (63 percent) had one or more students enrolled in an online course, according to a new survey by the Sloan Consortium. Another 20 percent of districts plan to launch such classes in the next three years.

The Sloan Consortium annually surveys higher-education institutions to track the growing phenomenon of virtual schooling--but this is the group's first-ever survey of online learning in elementary and secondary education. It's also one of the first K-12 studies to look at both fully online and "blended" courses, which combine online learning with traditional, face-to-face instruction. Nearly a third of districts (32 percent) said they had one or more students enrolled in a blended course.

"We are seeing a shift in how our children are learning--from a strictly classroom setting to a culture that includes online learning," said Frank Mayadas, president of the consortium. "Districts foresee that, over the next two years, online enrollments will increase by 19 percent and blended enrollments will go up by 23 percent."

Many of those who took part in the survey said they liked the combination of online and face-to-face instruction, because it allows for more oversight and stronger interaction between teachers and students. "We have discovered that blended courses are more successful because of the personal contact and group learning, along with close and direct [physical] monitoring by an instructor," one respondent said. Another said: "Hybrid courses have allowed for greater [student] engagement and encouragement."

The survey results also suggest that online learning is meeting the specific needs of a range of students, including those who need extra help, those who want to take more advanced courses, and those whose districts do not have enough teachers to offer certain subjects.

The survey, developed in collaboration with Hunter College and Babson College and funded by the Alfred P. Sloan Foundation, consists of responses from 366 public school district chief administrators representing two million students nationwide.