Research
Through partnerships with leading universities and research institutions, we continuously evaluate outcomes, share findings, and use evidence to guide our support of local leaders working to transform their education systems.
A growing body of research from across the country shows a clear picture about charter schools’ impact. Independent studies consistently show that urban charter schools significantly boost achievement for students of color and those from low-income communities, with these positive effects extending beyond individual schools to benefit entire school districts. Even more encouraging, students who attend charter schools are more likely to graduate high school, complete college, and earn higher wages as adults.
This landmark study shows that New Orleans school reforms dramatically improved student outcomes across the board: academic achievement increased by 11-16 percentiles, with gains continuing through high school (3-9% higher graduation) and college (8-15% higher entry, 4-7% better persistence, and 3-5% increased graduation rates).
This rigorous analysis of DC student achievement (2006-2013) reveals significant math improvements following mayoral control, with less than 10% attributable to changing demographics. Notable gains occurred across student groups—especially among affluent Black and Hispanic students—and even existing students showed substantial progress, countering the notion that improvements merely reflect new higher-performing enrollees.
This comprehensive study of Denver Public Schools' system-wide reforms (2008-2019) documents extraordinary results: students gained the equivalent of an additional full school year to year and a half of learning compared to peers in similar Colorado districts. The research documents effects "among the largest ever observed in educational research," demonstrating that Denver's reforms were among the most comprehensive and effective in American educational history.
This study of 41 urban areas across 22 states finds that urban charter schools deliver significantly stronger academic growth than traditional public schools—equivalent to 40 additional days of math learning and 28 additional days of reading annually. These benefits are particularly pronounced for Black, Hispanic, low-income, and special education students, with positive impacts increasing over the study period.
Nearly all randomized controlled studies of urban charter schools demonstrate positive academic effects on student achievement.
While charter schools overall perform similarly to traditional public schools, urban charters and those serving disadvantaged populations show substantially larger achievement gains—effectively narrowing educational gaps for low-income and minority students.
Boston's highly effective charter schools successfully reproduced their strong academic results at new campus locations, with lottery-based studies confirming that replication schools generated similarly large achievement gains as their original campuses. Despite charter market share doubling, the sector's overall effectiveness actually increased.
Charter students gained nearly half a year more learning on NAEP assessments between 2005 and 2017 compared to district school peers, with African American and low-income students experiencing the most significant improvements.
This analysis of 17 lottery-based studies reports that urban charter schools consistently produce positive academic gains, particularly for Black, Hispanic, and low-income students. Schools adopting "No Excuses" practices demonstrate the strongest performance gains and improved longer-term outcomes including increased college enrollment.
This comprehensive review of 40 lottery-based studies reveals that charter school attendance generally improves academic achievement and four-year college enrollment, with urban "high expectations, high support" schools showing the strongest gains.
Meta-analysis shows that charter school growth produced either positive or neutral effects on student achievement in traditional public schools across 15 of 16 regions studied
Public charter growth led to increased instructional spending in traditional public schools along with modest academic benefits for non-charter students. A 5 percentage point rise in charter enrollment boosted non-charter student scores by 0.03 standard deviations in math and 0.02 in English.
This causal analysis reveals that traditional public schools experience significant academic gains when charter schools open nearby, with effects strengthening with proximity. Co-located schools show the largest benefits, with improved performance in both subjects and reduced grade retention. Contributing factors include increased funding, higher academic expectations, and improved school climate—suggesting charter proximity benefits all students.
Districts where public charter schools open see improved graduation rates and higher math and reading scores across all publicly funded schools—suggesting positive effects that benefit students throughout the educational system.
Families across all grade levels in New Orleans prioritize three key factors when selecting schools: proximity to home, demonstrated academic excellence, and robust extracurricular programming that enriches student experience beyond core academics.
Washington D.C. parents make strategic school selections based on a multifaceted evaluation that weighs convenient location, academic performance metrics, and student demographic composition—including specific consideration of racial and socioeconomic diversity within the school community.
Analysis of New York City's high school selection process indicates that parents consistently prioritize schools with high-achieving peers (as measured by absolute test scores) rather than schools that demonstrate greater effectiveness at improving student growth.
Newark's reform strategy shows that opening new schools and closing low-performing ones led to bigger student achievement gains than trying to improve existing struggling schools.
School closures helped students when they could attend new, high-quality schools afterward. However, when students had no better options available after their schools closed, their academic performance actually declined—highlighting that closure alone isn't enough without ensuring good alternatives.
After schools closed, students who enrolled in better schools saw clear academic improvements. In contrast, students who ended up at similarly low-performing schools showed no gains.
Students who would have attended closed high schools in New York City saw their graduation rates jump by 15 percentage points when they attended different schools instead.
New York City's smaller high schools significantly boosted both college enrollment and students' ability to stay in college.
When struggling schools in New Orleans and Tennessee were restarted as charter schools, student test scores improved significantly compared to the original schools
Meta-analysis reveals a nuanced relationship between test scores and life outcomes: schools producing positive and neutral test score impacts both improved students' educational attainment, while only schools with negative test score impacts failed to boost long-term outcomes.
Lottery-based research demonstrates long-lasting benefits from Noble Network charter schools in Chicago, with students offered admission 10 percentage points more likely to attend college and 9.5 percentage points more likely to persist through at least four semesters—strong evidence of sustained impact on higher education access and persistence.
Students randomly selected to attend KIPP middle schools were approximately 7 percentage points more likely to enroll in four-year colleges than lottery losers, with effects nearly doubling (to 13 percentage points) when measuring impacts for students who actually attended. KIPP also showed positive but statistically insignificant effects on two-year college persistence.
Analysis of nearly 200 randomized field experiments identifies four consistently effective interventions for improving student achievement: early childhood education programs, high-dosage tutoring, carefully structured teacher professional development, and charter schools.
Recent quasi-experimental research definitively answers a long-debated question: increased school funding directly improves student outcomes. This comprehensive analysis reveals consistent causal relationships between higher school spending and improved student achievement across diverse contexts and methodologies.
This longitudinal analysis (1945-2013) shows court-ordered school desegregation significantly improved life outcomes for Black Americans without affecting whites. Desegregation increased Black Americans' educational and occupational attainment, college quality, and earnings while reducing incarceration and improving health. These benefits stemmed primarily from improved school resources, including smaller classes and increased funding.
Our research efforts focus on measuring the tangible impacts of school system reforms on student learning and long-term outcomes, including post-secondary attainment, employment, and earnings. While these metrics are valuable, we also recognize that education serves an additional purpose—instilling values, mindsets, and habits that help children lead meaningful lives. These crucial attributes are inherently difficult to measure, which is why we don't believe in universal metrics that claim to capture all aspects of quality education. We try to balance these two approaches in our work. We work with researchers to examine which schools are increasing student learning and leading to better life outcomes, as well as which schools parents want most for their children.
High-quality, non-profit public charter schools increase educational opportunity for low-income students in urban areas. Very few public policy innovations succeed at scale, which is why we believe public charter schools, now serving millions of students, represent one of the most important breakthroughs in public education. Research clearly shows that these schools increase academic achievement for low-income students, improve as they grow, and benefit traditional public schools. It's exceptionally rare to find an innovation that works best for those who need it most while improving as it scales. Non-profit public charter schools have achieved this remarkable feat while simultaneously passing both rigorous research evaluations and the essential test of parent demand—families actively choosing these schools for their children.
In the next phase of our work, we're investigating whether comprehensive urban school reform can improve all public schools in a city. Specifically, we're examining if citywide academic performance improves when municipalities increase the number of schools governed by non-profit organizations, implement enrollment systems that provide families with transparent information on school options and quality, and selectively intervene to improve underperforming schools. Cities like New Orleans, Washington D.C., Denver, and Newark have already adopted versions of this approach with promising results, despite their significant differences in politics, leadership, and public school governance. Our research now aims to determine if these positive outcomes can be replicated as additional cities implement similar reforms, and importantly, whether these initial student achievement gains will translate into meaningful improvements in post-secondary attainment and other long-term life outcomes.
The relationship between test scores and long-term life outcomes remains an area rich for exploration. Our ongoing research examines how standardized measures translate to college enrollment, graduation rates, and career earnings. Current evidence indicates that while schools with significantly decreased test scores don't improve postsecondary success, both schools with neutral and positive impacts on test scores have demonstrated the ability to enhance long-term outcomes. This pattern aligns with our understanding that severely underperforming schools create substantial risks—where students often lack basic skills, may encounter unsafe environments, and face higher dropout rates. At the same time, we recognize that academic metrics represent just one dimension of education; we're actively investigating how schools might develop other crucial skills that help.
While we are optimistic about our approach, it is not the only promising way to improve public education. Rigorous evaluations have shown that early childhood education, small group tutoring, and managed professional development for teachers can significantly raise student achievement. Research also demonstrates that higher spending on public education can increase test scores and high school graduation rates, particularly for low-income students, and that integrated schools improve both academic and adult outcomes. We are especially optimistic about innovations at the high school level, where much more can be done to create better transitions for students to thrive in careers and postsecondary education. We remain hopeful that some of these approaches will achieve success and be implemented at greater scale. Lastly, we recognize that K-12 education is just one piece of the puzzle in improving our country. While this remains our focus, we hope that others achieve amazing breakthroughs in public and private sector innovations across the broader landscape.
