Vocabulary Intervention for Students With Learning Disabilities in Grades 3 to 8: A Synthesis of 50 Years of Research.

This systematic review examined 63 vocabulary interventions for students with learning disabilities (LD) in Grades 3 to 8, reported 1978-2023. The review focused on instructional approaches, depth of processing, dosage, outcome measures, and study quality. Interventions included direct (n = 33), mnemonic (n = 20), strategic (n = 6), or combined (n = 4) approaches. Interventions lasted no more than 14 weeks, with the exception of one multiyear program. Mnemonic instruction was the most time-efficient, followed by direct, combined, and strategic approaches. Twenty-one studies (11 group design, 10 single-case design [SCD]) met quality standards. Standardized effect sizes on researcher-designed vocabulary measures ranged from 0.13 to 3.04 in group designs; seven SCD studies showed functional relations on vocabulary. Five of the 21 studies also included researcher-designed comprehension measures, with standardized effects for comprehension ranging from 0.41 to 1.51 in group designs, and two SCD studies demonstrating functional relations. Direct instruction emerged as a common and effective method for improving vocabulary and, occasionally, comprehension. Mnemonic instruction also yielded strong vocabulary outcomes, though the supporting research is dated. Strategic and combined approaches were underrepresented and warrant further investigation to better understand their potential for enhancing vocabulary and comprehension for students with LD.