Testimony of Eryn Heying, Executive Director of MIT Blueprint Labs, on Massachusetts Charter Public School Research

Good afternoon, Chair Gordon and members of the Committee. Thank you for the opportunity to testify today. My name is Eryn Heying, and I am the Executive Director of MIT Blueprint Labs, a research group focused on public policy and education. Our team, which includes three Nobel Prize-winning researchers, has studied charter schools in Massachusetts and across the country for more than a decade. We have published over twenty peer-reviewed studies on Massachusetts charter schools.¹ These use rigorous lottery-based methods: when oversubscribed schools admit students by lottery, we can compare applicants who receive a seat with those who do not. This approach, similar to randomized trials in medicine, isolates the effect of attending a charter school from other factors such as student motivation or background. The findings are clear: Massachusetts charter schools, particularly in urban centers, generate substantial benefits. In Boston, charter middle schools raise achievement by about 0.2 standard deviations in English and 0.4 in Math²—these are among the largest per-year standardized test score gains ever documented using a randomized research design, and are large enough to close long-standing racial and income achievement gaps. At the high school level, students are more likely to take Advanced Placement courses and score higher on the SAT.⁴ These impacts are greatest for low-income students, students of color, and students receiving special education services. Charter schools also increase college enrollment and degree completion, showing long-term effects.⁵ At the same time, not all charters are equally effective—Boston and other urban schools have the strongest results.³ Finally, we find no evidence that charter expansion harms district finances or student outcomes.⁶ With state reimbursements, district students may even experience small achievement gains. In sum, Massachusetts charter schools—especially the most effective urban schools—have delivered meaningful benefits, particularly for underserved students.