Constant Time Delay and Interspersal of Known Items to Teach Sight Words to Students with Mental Retardation and Learning Disabilities

Abstract

This study compared efficacy and efficiency of constant time delay and interspersal of known items to teach sight words to students with mild mental retardation and learning disabilities. Procedures were counterbalanced across time of day and instructional groups in a parallel treatments design. For students with mild mental retardation, constant time delay was more effective and efficient based on words learned, percentage of errors, instructional time, and sessions through criterion. For students with learning disabilities, procedures were equally effective, but constant time delay was more efficient across most measures. Results support effectiveness of constant time delay and suggest that interspersal of known items may be more effective for students with learning disabilities than students with mild mental retardation.