School Choice & Charters

Charter Schools Now Outperform Traditional Public Schools, Sweeping Study Finds

By Libby Stanford — June 06, 2023 7 min read
Achievement First charter school is seen Saturday, March 7, 2020, in Providence, R.I.
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Charter schools have evolved over the course of two decades, and their students now show greater academic gains than their peers in traditional public schools, according to a new report from a group of researchers who have studied the evolution of charters since 2000.

The study, which examined student performance in 6,200 charter schools from 2014 to 2019, marks a turning point in the understanding of charter school performance. It’s the third study of its kind from researchers at the Center for Research on Education Outcomes, or CREDO, after the center’s earlier studies found that charter school students performed either worse than or about the same as their peers in traditional public schools.

From 2014 to 2019, charter school students gained, on average, the equivalent of 16 days of learning in reading and six days in math over their peers in traditional public schools. Eighty-three percent of charter school students performed the same as or better than their peers in reading, and 75 percent performed the same as or better in math, according to the study, which includes data from 29 states, New York City, and the District of Columbia.

The average charter school performance in reading and math has only grown since 2000-01, showing a long-term pattern of charter schools outperforming the national trend, which showed student performance plateauing during that same time period, as measured by the National Assessment of Educational Progress, or NAEP.

The researchers used standardized testing data from state education agencies and schools to match 1,853,000 charter students with peers in the traditional public schools they otherwise would have attended to compare charter and traditional students.

“That is really pretty remarkable in the sense that if you picture in your mind the NAEP line over the same 15-year period, that’s flat. We didn’t get a lot of traction as a nation,” said Margaret “Macke” Raymond, founder and director of CREDO, which operates out of Stanford University. “If you look at the traction [charter] schools have had over the same period, for me, it’s not specifically, ‘yay, rah, charter schools.’ It’s, hey guys, there’s a way to build that improvement line.”

Study shows a long-term trend

CREDO has studied the performance of charter schools as the publicly funded but independently run schools have proliferated and become a mainstay in the nation’s educational landscape.

The first charter school opened in Minnesota in 1992. Some 3.7 million students attended 7,800 charter schools in the fall of 2021, according to the National Center for Education Statistics. Their enrollment more than doubled between 2010 and 2021, and the number of schools grew by nearly 50 percent in that time. Eight percent of public schools were charters in the fall of 2021, up from 5 percent a decade earlier. The schools also grew more racially diverse in that time.

While traditional public school enrollment declined by 4 percent in the first year of the pandemic, between fall 2019 and fall 2020, charter school enrollment grew 7 percent.

CREDO’s first study, conducted from 2000-01 through 2007-08, showed that charter school students lost six days of learning in reading and 17 days of learning in math measured against the average 180 days of learning a traditional public school student would receive.

Raymond described the results of that first study, released in 2009 as the administration of then-President Barack Obama began a major push to expand charters, as a “cold shower” for charter school leaders and advocates.

The next study, analyzing school performance from 2006-07 through 2010-11, showed slight improvement. Charter students gained an additional six days of learning in reading, outpacing traditional public school students, and lost three days of learning in math, effectively breaking even with traditional public school students’ average of 180 days of learning.

But Raymond and her team were hesitant to interpret those results as a trend.

The 2023 study, however, confirmed a positive trend for student performance in charter schools.

“We needed the third study in order to be able to say, ‘Look, this isn’t an accident, this isn’t a fluke,’” Raymond said. “This is actually a persistent condition of the context about charter schooling.”

The study tells a story of how the charter school sector improved after the 2009 study.

Early on in the creation of charter schools, charter school authorizers—the entities that allow charter schools to open and oversee them once they’re running—and charter management organizations that operate schools were focused on opening as many schools as possible, Raymond said.

Following the 2009 report, many charter school authorizers—which include school districts and state boards—found themselves looking more critically at the model and focusing on improving schools that already existed rather than creating new ones.

Organizations like the National Association of Charter School Authorizers helped charter school authorizers become more rigorous and increase their focus on accountability, Raymond said.

“What happens from 2010 to present day, is that the authorizer side of the equation gets really serious,” Raymond said.

Charter school authorizers should be “governors of quality,” the study says, pushing charter schools to innovate and improve outcomes for students.

The states and cities that really committed to improving school outcomes are reflected in the data of the latest study. Raymond pointed to New York, where charter school students gained 75 days of reading and 73 days of math from 2014 to 2019 over traditional public school students. Rhode Island and Tennessee also saw significant gains, with students in Rhode Island gaining 90 days of reading and 88 days of math and Tennessee students gaining 33.5 days of reading and 39 days of math.

Charter school authorizers “got very serious about doing a good job of reviewing applications at the beginning, and being really tough about who gets in the game. But even more so, they’re very serious about review and action at the point of renewal,” Raymond said.

Not every charter school is succeeding

While the study provides an overwhelmingly positive outlook on charter schools, the sector’s performance isn’t universally positive.

Full-time online charter schools in particular failed students in both reading and math, according to the study. Students in online charter schools lost 58 days of reading and 124 days of math learning compared to traditional public school student learning days while students in brick-and-mortar charter schools gained an average of 22 days of reading and 15 days of math.

“The learning there is just completely dreadful,” Raymond said. “The kids in online schools on average lose a third of the year in reading and two-thirds of a year of growth in math. That’s horrific.”

Charter schools are also failing to serve special education students, a group that has historically been underserved by the public school system as a whole. Those students lost 13 days in reading and 14 days in math.

Traditionally, a lower percentage of charter school students have required special education than traditional public school students, and charter schools have been accused of enrolling only students with less severe disabilities.

Nearly 11 percent of charter school students qualified for special education in 2016, compared with nearly 13 percent in traditional public schools, according to an analysis of federal data by The Center for Learner Equity. A previous analysis by the nonprofit, which focuses on equitable education access for students with disabilities, found that charter schools enrolled fewer students with developmental delays, multiple disabilities, and intellectual disabilities than traditional public schools.

Meanwhile, other students in special populations attending charter schools have seen growth, according to CREDO’s analysis. Students in poverty gained 23 days of reading and 17 days of math while English learners gained six days of reading and eight days of math compared with their peers in traditional public schools.

“There’s a slice of kids in the charter schools in special education that are not being served as well as they would have been had they gone to district schools,” Raymond said. “This is a consistent and persistent finding, and it’s something that the community of charter schools has to address.”

Lessons for traditional public schools

Raymond doesn’t see the study as a full endorsement of charter schools, but rather an indication that the flexibility afforded to charters—and flexibility they afford their staffs—can lead to better outcomes for students.

“The largest source of the improvement is that existing schools improve over time, not that we get much better schools coming into the mix,” she said. “In order to do that, school teams have to have this capacity to adapt... It’s not that you’re doing revolution, it’s that you’re doing evolution. You’re trying little things here and there.”

That lesson may be especially important following the COVID-19 pandemic. The study was conducted before the pandemic took place, but indicates that schools with the capacity to try new things and adapt to changing circumstances can produce positive student outcomes, Raymond said.

“The bigger lesson now in the post-COVID world is, hey guys, if you’re looking for a way to improve outcomes for kids, here is an absolutely demonstrated framework that you can look at and maybe apply it in other contexts,” Raymond said.

A version of this article appeared in the June 14, 2023 edition of Education Week as Charter Schools Now Outperform Traditional Public Schools, Sweeping Study Finds


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