Those of us who earlier expressed grave misgivings about the proposal by K12 Inc. to open a virtual online school in Cabarrus County now find new reasons for doubt.

A recently announced assessment, done by a nonprofit group called the National Education Policy Center, produced dramatic and disturbing results. During the 2010-11 school year, 52 percent of conventional, brick-and-mortar public schools nationwide met the federal standard for Adequate Yearly Progress. By contrast, fewer than 28 percent of schools managed by K12 measured up.

But there was more: Graduation rates at K-12 Inc. schools are 49.1 percent. This compares with 79.4 percent of regular schools in the states where K-12 operates.

Big Questions of Accountability

This is not to knock online schooling in general, which serves a valuable purpose in some cases — especially when students have special personal needs or require specialized courses that are not physically available in their area. Online classes are also enjoying a boom at the college level — where they may also make sense where appropriate.

But K12 is another kettle of fish altogether. Operated from out of state, it would have set up an entire virtual school, offering classes from kindergarten through high school. It is of far more than local interest, since it would seek to recruit students from anywhere in the state. It would also have raked in more than $18 million in federal, state and local tax money for next school year.

K12 operates in 29 states, enrolling more than 105,000 students in 59 such full-time schools. The ambitious size of its operation makes it larger than any other private education management organization in the United States. The very scale of the Cabarrus proposal, which seemed to have appeared rather suddenly out of nowhere, raised doubts here and elsewhere. Concerns were also expressed about the accountability of the operation, given the fact that so much public money was involved.

Look Closer Before We Leap

An administrative judge earlier ruled that the N.C. Board of Education had failed to act in time on the application by the “school,” if that’s what you call it. Wake County Superior Court Judge Abraham Penn Jones later reversed that ruling. This means K12 is apparently still at liberty to start up the Cabarrus operation next year.

But the new report about K12 Inc.’s performance provides new reason to step back and take another look before rushing to approve its North Carolina plans. The latest findings, by the way, come atop an earlier controversy that arose when it was revealed that K12 received nearly a million dollars in public funds for students that were never enrolled in its program — or even lived in other states. Clearly some regulators are asleep at the switch.

It comes as no surprise that the company disputes the critical report, charging that the nonprofit group producing it failed to take into account the fact that many students are signed up for the online program because they are already doing poorly academically. But there are too many danger signals here to brush aside.

K12 would appear to be raking in plenty of dough elsewhere for its dubious services. Despite the faddish popularity of charter schools of all kinds, this is a case where North Carolina authorities should take plenty of time to look before they take what could be a very unwise and harmful leap.