Evidence for a literacy intervention for students with intellectual and developmental disabilities

Evidence for a literacy intervention for students with intellectual and developmental disabilities

First Author: Jill Allor -- Southern Methodist University, Simmons School
Additional authors/chairs: 
Stephanie Al Otaiba; Carlin Connor
Keywords: Intellectual Disability, Intervention, Early Literacy, Developmental Disabilities, Text Characteristics
Abstract / Summary: 

Purpose: The purpose of this study was to conduct a meta-analysis of three years of single-case design pilot studies to examine the effects of a comprehensive literacy intervention on word recognition. Participants were 18 students with intellectual and developmental disabilities ranging in age from 6 to 13.
Method: The research design was a within case multiple baseline across level. The curriculum used includes specially-designed early readers, along with brief instructional lessons delivered by teachers and reinforcement activities led by paraprofessionals or tutors. Across 18 cases for sight words and 8 cases for decodable words, our multiple baseline across levels design resulted in 67 and 27 studies overall. The data obtained from each study was used to estimate the intervention effect. Coefficient Tau is a rank-order correlation between the experimental phase and the repeated measures, and is considered an acceptable single-case experiment effect size when properly adapted as a percent non-overlapping coefficient.
Results: For each case, our results indicate consistent moderate-to-strong positive effects for both sight words and decodable words. The mean effect size Taubc across the 18 sight word cases ranged from 0.44 to 0.86, with an overall mean Taubc of 0.73. The estimated Taubc across the 8 decodable word cases ranged from 0.47 to 0.90.
Conclusions: There is a clear functional relation between the intervention and increases in both sight words and decodable words. Effects were clearer for sight words than decodable words. These findings demonstrate clear promise of the effectiveness of the literacy program for students with ID.