Programs that offer families public funds to spend on private education expenses are becoming bigger, more common, and more complex.
Debates about these programs are dominated by claims from supporters and opponents, many of which leave little room for nuance. Academic research can help separate hype from reality—but figuring out what the research actually says can be a challenge even for the researchers themselves, not to mention advocates, critics, policymakers, and journalists who cite studies in their work.
More than half of states now have at least one private school choice program, according to Education Week’s private school choice tracker. Many have several. Twelve have programs that currently or eventually will accept applications from all students in the state.
This school year, for the first time ever, more than 1 million of the nation’s 50 million K-12 children took advantage of private school choice, according to the nonprofit EdChoice, a leading advocate.
A closer look at the private school choice literature reveals some consistent findings as well as a number of gaps in understanding. That’s in part because measuring the effects of private school choice on outcomes like student-test scores is no easy task.
Many states either don’t require students accepting funds from these programs to participate in state exams that public school students take, or they don’t report test-score data from private schools. Researchers often depend on state education departments to supply data suitable for rigorous analysis, but not all states are eager to help. And many private school curricula differ from public schools, making apples-to-apples comparisons of test scores less meaningful.
Meanwhile, assessing the research consensus can be challenging due to the proliferation of studies from advocates of private school choice, which tend to offer a rosier view of these programs than truly independent analysts do.
With those caveats in mind, here’s a look at what we know—and don’t yet know—about private school choice.
What we know about the academic achievement of students using private school choice
Studies that examine the early days of private school choice programs, from the 2000s, show that participating students—largely low-income students from urban areas—modestly outperformed their public school peers on standardized tests. More recent peer-reviewed studies, looking at programs that are newer and larger, have shown the opposite.
In 2002, for instance, researchers found that Black students in New York City, the District of Columbia, and Dayton, Ohio, all saw bigger improvements in test scores upon accepting private school vouchers than did their peers who stayed in public school.
But more recent examinations of private school choice programs have identified notable achievement gaps.
In Louisiana, researchers in 2018 attributed slightly lower math scores among participants in private school choice to “low-quality private schools” that the state approved to participate in the voucher program. One study found that “substantial” negative impacts on math test scores of private school choice participants got smaller after one year but were still present after four years.
In the District of Columbia, researchers for the federal government analyzed data from the first year of the program and found a “statistically significant negative impact on the mathematics achievement” of participating students.
And in Indiana, researchers found that private school students’ math test scores dropped slightly during their first year using a private school voucher, compared with students in a public school. That gap “persisted regardless of the length of time spent in a private school.” English scores didn’t take a similar hit, researchers found.
How competition from private school choice affects public schools
A handful of studies have largely reached the same conclusion: Students who enroll in private school choice programs aren’t substantially more or less likely to attend college than their peers in public schools. That said, several studies suggest a more competitive education marketplace improves public school students’ academic performance.
In Louisiana, where researchers found big differences in test scores between private school choice participants and public schools, little difference appeared in educational attainment between those two groups. The same was true in the District of Columbia, multiple studies show.
But researchers have found on several occasions that private school choice programs might be doing more to help students from public schools than their harshest critics realize.
The introduction of Florida’s private school choice program led to higher test scores and lower rates of absenteeism among public school students, particularly but not exclusively for low-income students, according to a study published last November. Researchers in Louisiana came to a similar conclusion a few years earlier.
Published studies so far have focused largely on the existence of these competitive effects without speculating much as to why competition sparks these improvements.
When it comes to comparing public schools and private schools, at least one set of researchers argues any differences can be attributed not to the schools but entirely to the different socioeconomic characteristics of students in the two sectors.
Who participates in private school choice programs?
So far, it appears the primary beneficiaries of universal private school choice programs in particular are wealthier families, who were typically excluded when eligibility for vouchers and education savings accounts was geared toward lower-income students and students with disabilities. Most private school choice recipients in the newer programs were already in private school prior to accepting state funds, according to state data and researchers.
In Ohio, one study of a state program that awarded vouchers to students from low-performing schools found that most recipients were low-income children or students of color. But some of the most economically disadvantaged people in the state were less likely than wealthier families to take advantage of the voucher opportunity even when they were eligible.
In Arizona, which has had a universal ESA offering for the last two school years, families in the wealthiest 10 percent of the state’s population participated in the program at five times the rate of families in the poorest 10 percent of the state’s population, according to researchers at Brookings, a left-leaning think tank.
A similar pattern holds true when looking at educational attainment. In the geographic areas of the state with the largest share of college graduates, participation in the ESA program was five times more common than in the areas with the smallest share of college graduates.
What private schools do when students qualify for public funds
Early evidence from universal programs suggests that private schools tend to raise tuition when states expand eligibility for vouchers and ESAs to all students. Some advocates claim that private schools poach the most gifted students from public schools, but researchers studying that phenomenon have yet to find substantial evidence.
When Indiana expanded its existing voucher program so that all the state’s students were eligible to apply, private schools responded by increasing prices by as much as 25 percent, according to a working paper published earlier this year from researchers at Princeton University.
“If a goal of ESAs is to extend private school access to new families, the substantial tuition increases they produce may limit access,” wrote authors Jason Fontana and Jennifer L. Jennings.
That research builds on findings from 2016 that show that private schools generate more revenue when states offer more money to families to send their kids to those schools.
On the other hand, researchers could find no evidence in 2023 that private schools were “skimming the cream” out of public schools by enrolling their most gifted students, thereby prompting a drop in public schools’ average test scores.
Those same researchers, however, did find evidence that private schools tend to push out the lowest-performing students receiving private school choice subsidies. A decade-old study found that students who return to public schools from private school choice programs tend to subsequently get higher test scores but end up in schools with lower-than-average performance, researchers found.
What we still don’t know about private school choice
Much of the private school choice research so far has examined voucher programs, which give parents money to spend on private school tuition. And in general, much of the research has primarily used data from the earlier, narrowly targeted set of private school choice programs, rather than the more expansive programs that have swept conservative state legislatures in the last three years.
Fewer studies have examined the newer iteration of private school choice known as “education savings accounts,” which can be spent on a wider range of private education expenses, including for textbooks, transportation, and materials for home schooling.
Other topics that appear ripe for more analysis include the ripple effects of private school choice on phenomena like racial and economic school segregation; state funding for public schools; and enrollment trends in public schools.
