The recent reauthorization of the Individuals with Disabilities Education Act (IDEA) into the Individuals with Disabilities Education Improvement Act (IDEIA) has had a profound impact on the manner in which schools provide services to their students. The reauthorization, coupled with the adoption of the No Child Left Behind Act (NCLB), emphasizes needed improvements in the general education and special education systems and requires that curricula and instructional tools demonstrate proven effectiveness. These recommended improvements have led to the birth of the Response to Intervention (RTI) model of service delivery.
The purpose of this study was to apply the regression discontinuity design to determine the effectiveness of the RTI model of service delivery for a group of first-grade students receiving Tier 2 intervention services in reading. An additional goal of this study was to determine the appropriateness of regression discontinuity as a method of analysis for the RTI model.
The independent variable for this study was participation in Tier 2 reading
services. The dependent variable was the students’ post-program level of reading
fluency, as measured by their performance on the spring administration of the Oral Reading Fluency (ORF) subtest of the Dynamic Indicators of Basic Early Literacy Skills (DIBELS). Students’ performance on the pre-program measure, the winter administration of the Oral Reading Fluency subtest of the DIBELS, was used to assign students to Tier 2 services. Out of 141 students, 21 met criteria for Tier 2 services and participated in the program group; the remaining 120 students participated in the control group.
Results of this study yielded standardized effect sizes of .176 and .128 for two models, suggesting that Tier 2 services were effective in increasing reading fluency for this group of first-grade students. The strengths and limitations of using the regression discontinuity design are discussed. The findings in this study added to current research on the effectiveness of Tier 2 services and appropriateness of using the regression discontinuity design.