Fidelity of Implementation and Instructional Alignment in Tier 2 Interventions: An Updated Review of Experimental Studies

Multi-tiered systems of support in reading (MTSS-R) allocate instructional resources to identify and address students’ needs. Tier 1 instruction is designed to meet the needs of most students, with more intensive standardized instruction provided in Tier 2 for students who need additional support. Prior research has emphasized the importance of high-quality Tier 1 instruction and alignment with Tier 2 interventions, but noted that few Tier 2 studies reported sufficient information to determine fidelity or alignment of school-implemented Tier 1 instruction. This review synthesized experimental studies ( k  = 26) published since 2011 and found that while reporting of Tier 2 intervention fidelity has improved, many studies provide limited information about school-implemented Tier 1 instruction. Nonetheless, more studies assess or actively manipulate Tier 1 instruction. Increased attention to the wider MTSS-R context of Tier 2 intervention has implications for practice and future research.