Citing the "disturbingly low performance" of many virtual charter schools across the country, two leading national charter organizations on Thursday called on state education officials to make tough policy changes to improve cyber education and close chronically troubled virtual schools.

The unprecedented action by the charter school community has special relevance for Pennsylvania, one of the nation's "big three" in cyber enrollment.

The state's 13 cyber charters enroll 35,250 students who receive instruction online in their homes. None of those schools met the state's most recent benchmark for academic performance.

California and Ohio are the other states with large cyber enrollments. New Jersey and Delaware have no cyber charters.

The National Alliance for Public Charter Schools in Washington was the lead group behind a 16-page report on cyber charters that is to be released Thursday morning.

It was joined by the National Association of Charter School Authorizers in Chicago and 50CAN, a nonprofit based in Washington that advocates for high-quality education. Both support the report's findings and recommendations for improving virtual charters.

The first cyber charters opened in the late 1990s. By August 2014, 135 such schools were operating in 23 states and the District of Columbia, and enrolled approximately 180,000 students.

"Though some full-time virtual charter schools can effectively serve the unique needs of the students they enroll, overall these schools are not producing great outcomes," Nina Rees, president and CEO of the alliance, said in a statement.

While some states have banned cybers, that limits parental choice, she said. "This is why we need a better regulatory framework to govern full-time virtual charter schools," Rees said.

The report pointed to evidence that researchers have been gathering about cybers for years, including recent comprehensive studies that found the vast majority of cyber charters perform worse than traditional public schools.

"Most striking and troubling in these reports is the finding of large-scale underperformance by full-time virtual charter schools," the report said. "If traditional public schools were producing such results, we would rightly be outraged. We should not feel any different just because these are charter schools."

The alliance and its partners said they support cyber schooling as an option for families who need it, but called on states to address the significant problems "instead of turning a blind eye to them."

Among other things, the report said that nearly a quarter of the cyber charters enroll more than 1,000 students, almost 70 percent are managed by for-profit companies, and most states fund cybers the same way as regular charter schools.

The report said states should limit the size of cyber charters and allow them to grow based on performance, and should develop funding formulas based on the actual cost of operating online schools.

In Pennsylvania, students' home districts pay the same amount to a cyber as to a regular charter that has a building and grounds. And because the state formula is based on how much a district spends to educate its own students, cybers are paid 501 different rates.

For example, Philadelphia pays $7,734 for each city student who attends a cyber; Lower Merion pays $18,023.

Each district pays a separate, higher rate for special-education students.

The report also calls for states to establish criteria for cyber enrollment to make sure the students who sign up for online schooling can find success.

The report's authors said, "It is increasingly clear that full-time virtual charter schools are not a good fit for many children. . . . Perhaps more than any other type of educational environment, full-time virtual charter schools require self-motivated students and highly involved parents."

As is the case in many other states, Pennsylvania law requires cybers to admit students whose families apply.

If enrollment criteria are not permitted under states' laws, the report said, officials should consider taking cybers out of the charter arena and making them "selective-enrollment public schools."

martha.woodall@phillynews.com 215-854-2789 @marwooda