Do State Dyslexia Laws Improve Reading Achievement? \ from Staggered Adoption with Corrected Treatment Timing

Abstract

Since 1995, 27 U.S. states have adopted dyslexia-related legislation ranging from awareness provisions to comprehensive dyslexia legislation (26 since 2010, plus Texas in 1995). This paper evaluates the causal effect of these policies on fourth-grade reading achievement using a staggered difference-in-differences design with NAEP data from 2003–2022. A critical methodological contribution is correcting treatment timing: because NAEP is administered January–March, laws effective mid-year cannot affect that year's assessment. Employing the Callaway-Sant'Anna (2021) estimator with corrected timing and 1,000 bootstrap iterations, I find a precisely estimated null average effect: ATT = 1.02 NAEP points (SE = 1.16). However, separating states that bundled dyslexia laws with comprehensive literacy reforms from "dyslexia-only" states reveals important heterogeneity. Among bundled reform states with evaluable post-treatment NAEP data (Mississippi, Florida, Tennessee), positive effects emerge, while dyslexia-only mandates show null effects. Alabama also adopted a bundled reform (2022) but has no post-treatment NAEP observation in the sample period. These findings suggest that dyslexia legislation alone—without accompanying curriculum reform, teacher training, and intervention requirements—do not improve aggregate reading outcomes. The policy implication is clear: effective early literacy policy requires comprehensive reform bundles, not piecemeal mandates.