Fordham Institute

Approximately 7.5 million U.S. students receive special education services in public schools—more than one in seven pupils nationwide. Its services cost roughly twice as much per pupil as general education and account for about one-third of federal appropriations for elementary and secondary education. Despite its scale, there has long been uncertainty about special education’s causal impact on student outcomes due to selection bias and methodological challenges. A new working paper from Boston University’s Wheelock Center (2026) helps fill this gap by applying rigorous causal methods to longitudinal administrative data to examine the impact of special education classification on student learning and educational progress.

The study revealed several notable findings. Most importantly, across all three states, students’ achievement trajectories declined prior to special education classification and rose sharply after they began receiving special education services. Taken together, this pattern suggests that special education services do not merely support students at a fixed level of performance, but instead help reverse ongoing academic decline. Additionally, student gains did not occur all at once but increased over multiple years. This gradual pattern was consistent with sustained improvements in underlying skill development rather than short-term test score gains. The findings indicate that special education enhances the productivity of instruction over time, not just short-term performance.