Two Rivers Public Charter School first graders listen during the weekly school community meeting seated on the floor in the common area known as The Green on April 11, 2012 in Washington, D.C. (Mark Gail/The Washington Post)

They’re in demand among parents who say traditional public schools have failed — but they’re not always successful. Their intense rate of growth has fueled an equally intense debate about the role they’ll play in the future of U.S. education. Advocates see their expansion as evidence that parents have a huge appetite for school choice. Critics see the beginning of the end of public education, with systems of neighborhood schools replaced by independent, privately run companies without the same obligation to teach the toughest students. A great deal of confusion surrounds charter schools. Here are some of the myths.

Myth No. 1

Charter schools are everywhere.

At its national convention this year, the NAACP called for a moratorium on charter school expansion. The Alliance to Reclaim Our Schools, a union-backed coalition, demands: "Stop flooding our communities with under-performing and unaccountable charter schools." The charter debate is front and center in the education reform wars, and you'd think that they're everywhere — a wave overtaking every community.

Yes, the charter movement is growing. And charters have a significant market share in an increasing number of cities, with New Orleans (where 93 percent of students attend charters) leading the way, followed by Detroit (53 percent), Flint, Mich., (47 percent) and Washington (44 percent). Forty-three states and the District have laws allowing for charter schools.

But in many parts of the country, charters are few and far between. About 3 million students are enrolled in approximately 6,800 charters, according to the National Alliance for Public Charter Schools. That's only about 6 percent of all public school students. Eight states have no charter schools, and five have fewer than 10. The debate is loud, but the market share is still small.

Myth No. 2

Charters are the brainchild of union-busting billionaires.

Critics of charter schools often accuse philanthropists — including Microsoft founder Bill Gates, entrepreneur Eli Broad, hedge fund manager John Arnold and the Walton family, heirs to the Walmart fortune — of fueling the rise of charter schools and other reform projects as a way to promote free-market ideology and undermine teachers unions. In Salon early this year, Diane Ravitch (a George H.W. Bush-era federal education official who has become perhaps the nation's most voluble charter critic) railed against Gates for using his wealth to push charters in Washington state. In the Huffington Post, Bill Bigelow argued that Charles and David Koch are involved with school reform because "they hate public schools."

It is true that deep-pocketed foundations have played a key role in the expansion of charter schools, through contributions to charters themselves and to the ecosystem of organizations that work with such schools. But charters were originally the brainchild of teachers union stalwart Al Shanker, who served as president of the American Federation of Teachers from 1974 to 1997. Shanker proposed charter schools in 1988, arguing that they would give small groups of teachers a way to dream up new methods of reaching the students for whom traditional schools were not working. Their successes and failures would hold lessons for other schools striving to improve. The first charter school opened in Minnesota in 1992.

Some charters have acted as Shanker envisioned, but in many states they haven't, rejecting requirements for teacher certification or barring collective-bargaining rights. Driven by a vision of market-based reform, charters have become not laboratories so much as competition meant to either spur traditional schools to improve or replace them. Just a few years after proposing charter schools, Shanker largely disavowed them, holding instead that schools would get better only by standardizing their goals — the same theory that underlies today's controversial Common Core state standards .

Myth No. 3

Charters are better than traditional schools.

Republican presidential nominee Donald Trump is a big fan of expanding school choice via vouchers and charters. "We will rescue kids from failing schools," he told the GOP convention in July. Books, articles and documentaries like "Waiting for 'Superman' " have created in the popular imagination a picture of charter schools with impossibly long waiting lists, offering an escape to children desperate for a better education in neighborhoods beset by crumbling traditional schools.

While it is true that some charter schools outperform traditional schools, it is also true that many charter schools fail. The Center for Research on Education Outcomes (CREDO) has produced a series of studies comparing academic results at charter and traditional schools. In 2013, CREDO found no difference nationally between traditional and charter schools in math, while in reading, the average charter school student gained the equivalent of an additional eight days of learning per year.

But there was wide variation. Among the charters CREDO studied, 31 percent were significantly weaker in math than their traditional school counterparts, 29 percent were significantly stronger and 40 percent showed no real difference. CREDO studies also show variation across state lines. In cities, charters tend to fare better: The average student in an urban charter school gains the equivalent of 40 more days of learning in math and 28 additional days in reading. But the average charter student in Texas and in Ohio — a state that has been notorious for allowing poor-performing charters to persist — learns less in math and reading each year than her peers in traditional schools.

Myth No. 4

Charter schools are public. Or private.

In August , a National Labor Relations Board majority ruled that a charter school in Brooklyn "was not established by a state or local government" and was, therefore, "not itself a public school." The board's lone dissenter argued that "charter schools operate as K-12 public schools" and should be treated as such since "they are substantially regulated under state and local laws, and they are overseen by state and local authorities." This is one of education's more bitter feuds, a semantic battle that underlines how important public education is to our nation's notion of itself. Advocates insist that charter schools are public because they are tuition-free and equally open to all children. Critics argue that charters are at the leading edge of an effort to privatize public education in the same way other government functions, such as prisons, have been outsourced to private companies.

Neither side is entirely right. Charters are a hybrid, and judges and regulators have struggled to figure out how they should be treated under the law. "Courts have had a difficult time determining their legal status because they exhibit both public and private characteristics," researchers wrote in a University of Massachusetts Law Review article last year. When charter students in Colorado, for instance, set a fire that destroyed private property, the property owners sued the school for negligence. The school argued that it was a public entity and therefore immune. A federal judge agreed, finding that the school's autonomy did not make it a private institution.

Often, the public- or private-ness of charter schools depends on state law. In many states, for example, charter schools are subject to sunshine laws, meaning their records and board meetings are open to the public. But not everywhere: In the District, for instance, charters are exempt from sunshine laws, which means journalists and parents often cannot access even basic information about how the schools spend taxpayer money.

Myth No. 5

All charters employ zero-tolerance discipline.

Many of the nation's most heralded charter school networks were built as "no excuses" schools that practice a broken-windows approach to discipline. Children are expected to abide by strict rules — walking in silent lines, eating silent lunch, sitting up straight, maintaining eye contact with teachers as they move about the room — and are punished for even small infractions. The suspension rate among charters nationally was 16 percent higher than among traditional schools in the 2011-2012 school year, according to the Civil Rights Project at UCLA.

But it has never been the case that all charter schools subscribe to the no-excuses, zero-tolerance philosophy. In the District in 2011-2012, the same year that charter schools were 72 times more likely than the traditional school system to expel a student, there were six charters that issued zero suspensions or expulsions, and 15 others that issued five or fewer.

Lately — amid growing concern over feeding the school-to-prison pipeline with expelled students, and over producing graduates ill-equipped to deal with the freedom and responsibility of college life — there's been a shift even among some stalwarts of the no-excuses approach. At Ascend charter schools in New York, kids no longer get in trouble for wearing socks that are the wrong color. In the District, charter schools' suspension and expulsion rates are dropping. Some KIPP schools now use restorative justice, which prioritizes working through problems over doling out punishment. Even Education Secretary John King Jr. — whose charter school in Boston is known for both its high test scores and high suspension rates — delivered a speech this summer calling on charter leaders to rethink their approach to discipline.

Twitter: @emmersbrown

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