Charter Schools Since Minnesota's 1991 Law: Results and Arguments

In 1988 the president of the American Federation of Teachers, Albert Shanker, gave a speech at the National Press Club in Washington proposing something new. Teams of teachers, he suggested, should be able to get permission from their district to start small, autonomous schools within the public system, try different ways of teaching, and be judged on whether it worked. He borrowed a word for these schools from a Massachusetts educator named Ray Budde, who had written about giving teachers "charters" to run programs. The idea traveled to Minnesota, where a group of policy activists and a Democratic state senator named Ember Reichgott Junge turned it into a bill. In 1991 Minnesota became the first state to pass a charter school law, and the next year City Academy opened in St. Paul, serving students who had dropped out or been pushed out of other schools. Within a few years Shanker had turned against what charter schools were becoming. The first champion of the idea was a union leader, and its sharpest opponents today are unions. Both facts are part of the story.

In short: Charter schools are publicly funded schools run independently of school districts under a contract with an authorizer. National research shows that on average charter students now do slightly better than similar public school students, with strong gains in some urban charters and serious losses in many online ones. The arguments over charters are also about money, governance, and who gets to be a teacher's employer.

What a charter school is, exactly

The terms in this debate get blurred, so it's worth being precise.

A charter school is a public school. It is funded with public money, may not charge tuition, and must admit students by lottery when there are more applicants than seats. It must give state tests and is covered by federal civil rights and disability law. What makes it different is governance. Instead of being run by the elected school board, it is run by an independent nonprofit board under a contract, the "charter," granted by an authorizer: sometimes the district, sometimes a state commission, a university or another body depending on the state. If the school fails to meet the terms, the authorizer can in principle close it.

Charter schools are usually freed from many district rules, and in most states teachers at charters are not covered by the district's union contract. Some charter teachers have organized unions of their own. A minority of charters are run day to day by for-profit management companies, which is permitted in some states and restricted in others.

Charters are not vouchers. Voucher programs send public money to private schools, which may be religious and generally don't face public testing and admission rules. That distinction, which often disappears in political arguments, matters for everything that follows.

What three decades of research show

The most cited national research comes from the Center for Research on Education Outcomes, known as CREDO, at Stanford. Its method compares each charter student with a "virtual twin" built from demographically similar students in nearby district schools.

CREDO's first national study, in 2009, was not good news for charter advocates. It found that a minority of charter schools outperformed comparable district schools, while a larger share did worse, and the rest showed no significant difference. Later national studies found the charter sector improving over time, and the 2023 study reported that on average charter students gained more in reading and math per year than their matched peers, with the largest advantages for Black and Hispanic students and students in poverty in urban schools.

Separately, economists have used admissions lotteries, the gold standard, to study oversubscribed charters in specific cities. Studies of Boston's charter high schools and middle schools by researchers at MIT and elsewhere found large gains in test scores for lottery winners compared with lottery losers, along with higher rates of taking Advanced Placement exams and attending four-year colleges. Similar lottery research in New York City found substantial gains at many charters there.

But the averages hide enormous variation:

1. Urban charters with strong management have produced some of the largest test score gains found in education research.
2. Suburban and rural charters on average show little difference from district schools.
3. Online charter schools are a different story entirely. CREDO's 2015 study of full-time online charters found that students lost substantial ground in math and reading compared with similar students in brick-and-mortar schools. Several large online charter operators have faced state investigations and repayment demands over enrollment counts.

So the honest answer to "do charter schools work?" is: some types in some places work very well, some do not, and the sector's average has improved partly because states closed weak schools and the stronger networks grew.

It is also worth remembering what the research cannot settle. Test scores capture some of what families want from a school. They say little about whether a child feels safe, whether a school's discipline is fair or harsh, or whether graduates thrive years later. Parents weigh all of that, and so should policymakers.

The case critics make

Teachers' unions and many progressive education advocates raise objections that go beyond test scores. They deserve to be stated at full strength.

Money. When students leave a district for a charter school, money follows them, but the district's costs don't fall proportionately. A building still needs maintenance, buses still run routes, and pension obligations remain. Districts with fast-growing charter sectors, especially those with declining enrollment, can face budget cuts that hurt the students who remain. This is sometimes called the problem of stranded costs, and it is real.

Who enrolls and who stays. Critics argue that some charters enroll fewer students with significant disabilities or English learners, and that students who struggle sometimes leave mid-year and return to district schools, which must take them. Research on this is mixed, and lottery-based studies address selection at entry, but attrition and backfilling policies vary by school and are a fair subject for scrutiny.

Governance. An elected school board, for all its flaws, answers to voters. A charter board answers to its authorizer. In cities where most students attend charters, parents can find themselves without a public body to petition about the schools as a whole.

Labor. Most charter teachers are not unionized. Unions argue that charters have been used to replace unionized jobs with lower-paid, less secure ones, and teacher turnover at many charter schools is high.

The case parents and supporters make

Charter supporters, including many parents of color in cities, answer with a different set of facts.

Demand. Charter schools in many cities have waiting lists. The families on them are disproportionately low-income and Black or Latino. When a lottery decides whether a child gets a seat at a school the family wants, the choice to cap charter growth is a choice about those families.

Results where it matters most. The strongest gains in the research have come for the students the public system has historically served worst. To parents, a system-level concern about district finances can feel remote when their child is reading at grade level for the first time.

Accountability that bites. Charters can be closed for poor performance; failing district schools rarely are. Supporters argue that this is a feature: a system that can close failing schools improves over time.

There is also an uncomfortable political fact here for progressives. Charter schools are more popular with Black and Hispanic Democrats than with white Democrats, according to repeated national polling. A position on charters that comes across to those families as protecting adults' interests rather than children's has cost the left trust in the communities it most wants to serve.

New Orleans, the all-charter city

No account of charter schools is complete without New Orleans, the one American city where nearly every public school became a charter.

Before Hurricane Katrina in 2005, the city's school system was among the lowest-performing in Louisiana and had a long record of financial mismanagement. After the storm, with the city emptied and the schools destroyed or damaged, the state took control of most of the city's schools through its Recovery School District and began turning them over to charter operators. The local school board fired its teachers en masse, a decision that later led to years of litigation and remains a source of deep bitterness, particularly among the Black teachers who made up most of the city's teaching force and much of its Black middle class.

Over the following decade, the share of students in charters climbed until, by the late 2010s, the city's public schools were almost entirely charter schools, eventually returned to the oversight of the elected local board. Researchers at Tulane's Education Research Alliance, studying the reforms, found substantial improvements in test scores, high school graduation and college-going compared with what would have been expected based on the pre-storm trend.

Both sides draw lessons from this. Supporters see proof that a system of autonomous schools, held accountable by a strong authorizer that closes failing ones, can transform outcomes in a city that had been failed for decades. Critics point out that the reforms came with a large infusion of money and outside talent, that the city's teaching force became younger, whiter and less rooted in the community, and that parents lost the neighborhood schools and elected oversight they had known. Both readings are grounded in fact. A reform can improve results and also do real harm to people and institutions. Honest accounting means holding both in view rather than letting either erase the other.

Where the fight has gone

The politics of charter schools have shifted several times. In the 2000s and early 2010s, charters had strong support from both parties, including the Obama administration, which encouraged states to lift caps on charter growth. By the mid-2010s, opposition grew on the left. In 2016 Massachusetts voters rejected a ballot question to raise the cap on charter schools by a wide margin, despite the strong Boston research. Teachers' strikes in Los Angeles and Oakland in 2019 included demands to limit charter growth, and some progressive candidates proposed moratoriums.

Meanwhile, many on the right have moved their attention from charters to vouchers and education savings accounts, which put money directly into private options. For charter supporters, that shift creates an odd squeeze: attacked by unions as privatization, and outflanked by conservatives who want to go much further.

Several states have also found middle ground. Some cities have created "unified enrollment" systems, letting families apply to district and charter schools on a single form. Some districts have formed compacts with charter networks to share buildings, training or special education services. Some charter networks have unionized teachers. These experiments don't settle the argument, but they show it doesn't have to be a war.

Why Shanker changed his mind

The man who popularized the charter idea became a skeptic within a few years, and his reasons are worth knowing because they still frame the debate.

Shanker's original vision was teacher-led: groups of teachers inside a district, with union support, trying new approaches and sharing what they learned. What developed instead, in many states, was a movement that saw charters primarily as competition for districts and an escape from union contracts, and that welcomed for-profit operators. Shanker also worried that charters would become a stepping stone to vouchers and that loose regulation would let weak schools open with little oversight.

Some of his fears came true and some did not. Weak charters did open, and many states were slow to close them. But the strongest charter networks have been nonprofits with serious academic programs, and the evidence from cities like Boston suggests that the idea of autonomous public schools held to account can produce real gains. Shanker's original question, how to give teachers room to innovate within a public system, remains one of the best ones in education.

Here is where we come down

This is an opinion, labelled as one. The question that matters most is not "charter or district" but "good school or bad school," and policy should be designed to grow the good ones and close or fix the bad ones, whatever their governance.

That means: strict authorizing, so weak charters don't open and failing ones close; much tighter rules on online charters, given the evidence; transparency on enrollment, discipline and attrition; funding formulas that cushion districts from sudden enrollment shifts; and respect for teachers' right to organize in any public school. It also means taking seriously the parents who choose charters, rather than treating them as pawns of a privatization agenda. Many of them are exactly the families progressive education policy is meant to serve.

What you can do

Charter laws, caps and funding rules are set by state legislatures, and authorizing decisions are often made at public meetings.

• Find out who authorizes charter schools in your state and when that body meets. Ask your state legislators about the state's charter rules and how online schools are held accountable; their phone numbers and recent votes are at the representatives lookup.
• Follow ongoing research and local fights over charter schools on the education topic page.
• Look for parent organizing groups, education advocates and teachers' organizations in your area in the organizations directory.
• If charter teachers in your city are organizing, union election results counted by the NLRB appear on the labor page, alongside union membership over time.