Students attend class at the Encore Academy charter school May 13, in New Orleans. Getty Images

Charter school policies in the United States need to include more transparency and accountability to combat the system's current privatization and profiteering, according to a report out Thursday from the National Education Policy Center, a nonprofit based in Boulder, Colorado. The center found that organizations and people associated with for-profit education management often use taxpayer dollars to "secure financial gain and generate profit by running charter schools, leading them to operate in ways that are sometimes at odds with the public interest," according to a news release.

The nation's more than 6,000 charter schools serve more than 2.2 million students. They're publicly funded but independently operated under different rules than public schools. For example, charter school operators don't have to hold open meetings or disclose certain finances like public governing boards do, allowing sketchy practices to go unnoticed, the center said in its report. The end result could be that money designated for improving classroom resources goes to "personal or business financial gain."

In one such scenario, a charter school affiliate might buy a building from a public school district with taxpayer money, but the public loses control of the building. "This particular type of transaction is usually legal, and it can be very logical from the perspective of each of the parties involved,” Rutgers University professor Bruce Baker said in the release. “But we should be troubled by the public policy that allows and even encourages this to happen.”

To address this and other concerns, the report's authors proposed reforming public policies. They called for expanding financial reporting requirements, opening meetings to the public and making sure all players involved work at arms' length.

“I think that understanding the nature of the charter school gravy train, as I call it, is extremely important for the public and policymakers," center director Kevin Welner told Al Jazeera.

The debate over the role charter schools should play in the U.S. is likely to continue with this week's passage of the Every Student Succeeds Act, the new iteration of the controversial No Child Left Behind education law. A news release from the National Alliance for Public Charter Schools praised the bill for including both funding for high-performing charter schools to expand and extra spending flexibility. “This is an exciting moment for the charter school movement,” the alliance's president and CEO, Nina Rees, said Wednesday.

President Barack Obama signed the bill into law Thursday, calling it a Christmas miracle.