The purpose of this study was to determine the effectiveness of a systematic, explicit, intensive Tier 3 (tertiary) intervention on the mathematics performance of students in second grade with severe mathematics difficulties. A multiple-baseline design across groups of participants showed improved mathematics performance on number and operations concepts and procedures, which are the foundation for later mathematics success. In the previous year, 12 participants had experienced two doses (first and second semesters) of a Tier 2 intervention. In second grade, the participants continued to demonstrate low performance, falling below the 10th percentile on a researcher-designed universal screener and below the 16th percentile on a distal measure, thus qualifying for the intensive intervention. A project interventionist, who met with the students 5 days a week for 10 weeks (9 weeks for one group), conducted the intensive intervention. The intervention employed more intensive instructional design features than the previous Tier 2 secondary instruction, and also included weekly games to reinforce concepts and skills from the lessons. Spring results showed significantly improved mathematics performance (scoring at or above the 25th percentile) for most of the students, thus making them eligible to exit the Tier 3 intervention.

As paraprofessionals gain more instructional responsibilities for individual students, feasible training strategies must be established to promote effective delivery of instruction. This train-the-trainer study was designed to teach paraprofessionals how to implement an evidence-based instructional practice under the direction of the classroom teacher. After receiving training from a university researcher, a special education teacher trained three paraprofessionals to implement constant time delay while teaching three students with multiple disabilities. The paraprofessional training consisted of a workshop, video modeling, and coaching with performance feedback. A single-case multiple baseline across paraprofessionals design was used to evaluate the effectiveness of the teacher-delivered training package. All paraprofessionals implemented the systematic instructional procedures with high levels of fidelity and accuracy after training. The special education teacher and paraprofessionals shared their perceptions on the highly effective training and value of the study through social validity surveys. Implications and limitations of the study are discussed.