Date Available


Year of Publication


Degree Name

Master of Science in Education (MSEd)

Document Type

Master's Thesis




Early Childhood, Special Education, and Rehabilitation Counseling

First Advisor

Dr. Melinda J. Ault


Constant time delay (CTD) and progressive time delay (PTD) are both evidence-based practices used to teach students with intellectual disability (ID). The prompt delay strategies have been used for instruction with academics, social, vocational, and communication skills. There is limited research regarding the differential effectiveness of the time delay variations for teaching academic content to students with ID. The present study compares the effects of CTD and PTD in the acquisition of academic content with four students with ID. An adapted alternating treatments design was used to compare the effectiveness and efficiency of the two procedures. Generalization was assessed across settings, participants, and materials. Results indicated that both strategies were effective but PTD was more efficient in regards to number of errors and average time to criterion.

Digital Object Identifier (DOI)