In the vast majority of schools around the United States, the academic gap between the highest- and lowest-achieving students has grown significantly since 2005, according to a recently released paper. The divergence was largely driven by stagnation among struggling students, which turned into steep learning losses during the COVID pandemic, the authors conclude.
The paper, circulated through Brown University’s Annenberg Institute in January, examines the learning of American students attending traditional public schools, charters, Catholic academies, and schools operated by the Department of Defense. While disparities between high-flyers and their lower-performing counterparts have widened across the board, they grew the fastest in public and Catholic schools.
Education leaders have warned of the trend toward increasing educational inequality for much of the last decade. During that time, each release of data from the National Assessment of Educational Progress — a federally administered exam commonly referred to as the Nation’s Report Card — showed lower-scoring test takers falling further behind; typically, top-scoring participants were also pulling away from the pack. By the end of the COVID era, differences in outcomes that were large at the outset had ballooned even wider.
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Patrick Wolf, an economist at the University of Arkansas and one of the paper’s co-authors, called his findings “demoralizing,” arguing that many American schools are clearly failing the students who most need their help.
“We expect and hope our public schools will be great equalizers and will reduce gaps between the top performers and the low performers, or the rich and the poor,” he said. “But over the last 20 years, we don’t see that in the data, and the gap has grown by a lot.”
‘We were not being heard’*
Wolf and his collaborators set out to measure what he referred to as the “90/10 gap” — the difference in NAEP scores between students who score at the 90th percentile (i.e., those scoring higher than 89 percent of their counterparts across the country) and those at the 10th percentile (those outscored by 90 percent of other test takers). To do so, they measured performance data from 2005, the first year that charter schools participated in the test, through 2024.
In all, the research team gathered scores from six million test takers through 10 iterations of the exam, controlling for factors like students’ race or socioeconomic status, as well as the educational background of their parents. Each NAEP administration generates data for both fourth and eighth graders in the core subjects of math and English.
Their estimates show that the academic gaps grew fastest in public schools. In each of the two decades between 2005 and 2024, scores for fourth graders at the 90th percentile increased by about four points in math and three points in reading; 10th-percentile scores dropped by roughly three and five points, respectively, resulting in a net disparity that was seven points larger in both subjects.
The Nation’s Achievement Inequality Report Card: An Assessment of Test Score and Equality Trends in Traditional Public, Charter, Catholic, and Department of Defense Schools (Annenberg Institute/Brown University)
While those calculations are somewhat technical, the bottom line is much starker: The already-substantial gap between the most advanced and most challenged fourth graders expanded by 1.3 years’ worth of learning gains between the Bush administration and the Biden administration. For eighth graders, the gap grew by one-half year of learning in both subjects over the same time period.
Similar divergences, though of somewhat smaller magnitude, were found in Catholic schools, which enroll approximately 3.5 percent of American K–12 students. During the period under study, the 90/10 gap grew by roughly 5 points per decade in fourth-grade math, six points in eighth-grade math, and four points in reading for both fourth and eighth graders.
Strikingly, the 90/10 gap for both sectors swelled even in the years preceding the pandemic. Those gaps, leading up to 2019, reflected both steady growth from children at the top of the heap, along with a lack of progress — and, in some cases, pre-COVID learning loss — from those at the bottom.
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Peggy Carr is a former commissioner of the National Center for Education Statistics, the research entity responsible for administering NAEP and reporting its results. Until February, when she was fired by the Trump administration along with most of the NCES staff, she regularly communicated with both politicians and the public about the meaning of the exam — including by highlighting the growth of the 90/10 gap and the persistently disappointing performance of children scoring at the 10th percentile.
In an interview with The 74, she said the discourse around NAEP was too focused on scores at the average, which tend to conceal wider swings among students far above or below that point.
“We were not being heard as clearly as we wanted to be,” Carr said. “We were trying to make it very clear that you need to look at the entire distribution for years, but it wasn’t the focus of policy makers.”
DoD schools, charters
Notably, both charters and DoD-administered schools saw a much slower drift between high- and low-achieving students, much of which appears to have been triggered directly by the pandemic.
In charter schools, the 90/10 gap grew by less than one point between 2005 and 2019 for fourth graders; for eighth graders, the gap actually shrunk during that period because students at the 10th percentile improved in performance faster than those at the 90th. The same narrowing was seen in fourth-grade math scores at DoD schools, where students across the spectrum made huge gains before the onset of COVID.
Tom Loveless, a veteran observer of K–12 schools and former director of the Brookings Institution’s Brown Center on Education Policy, called those results impressive, but noted that the lessons that can be drawn from the charter and DoD sectors were limited. Collectively, they account for only about 8 percent of America’s K–12 students, and parents enrolling their children in them can differ dramatically from the public at large.
“If you work for the Defense Department, your employer is running the school,” he observed. “Your superior officer can call you up and say, ‘Your kid is acting up,’ and something’s going to be done about it quickly.”
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Perhaps the most dispiriting part of the trend is that America’s 90/10 gap exploded so visibly at the same time that achievement gaps — whether along racial, socioeconomic, or other lines — transfixed the education world. Educators, office holders, policy wonks, and activists all put academic disparities at the heart of their work during the years between the late-1990s and the mid-2010s.
For a large portion of the “education reform” era kicked off by the 2002 passage of the No Child Left Behind law, underperforming students did see significant progress, Wolf said. But the years since 2013 have been marked by a pronounced reversal of those gains.
“By definition, there will always be a gap between the students performing at the 90th percentile and students performing at the 10th percentile,” he acknowledged. “But we don’t want it to be wide, and we don’t want it to be getting wider.”
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