The Spanish- and English-Language Literacy Impacts of Descubriendo la Lectura across Three Experimental Replications

We present findings across three randomized trials of Descubriendo la Lectura (DLL), an intervention designed to improve literacy skills of Spanish-speaking first graders struggling with reading. DLL is a one-to-one Spanish-language literacy program lasting 12–20 weeks offered to a school’s lowest performing emerging bilingual first graders. Directly replicating procedures across three cohorts, we examined Spanish and English literacy outcomes for approximately 400 students across 30 schools, 10 districts, and five states. Analyses revealed statistically significant effects of student-level assignment to DLL on all 11 Spanish-language outcomes, with an average impact of d = 0.57. Impacts across the four English-language outcomes were positive but not statistically significant. Descriptive results suggest that the Spanish-language impacts are reliably replicated, most likely due to the intervention’s strong implementation supports.