Implementation Science in Elementary Literacy: Fidelity, Adaptations, and Instructional Challenges

Fidelity of implementation, how closely instructors follow intervention protocols, is critical for translating evidence-based educational programs into meaningful student outcomes. This study examined factors influencing teachers’ fidelity in an asynchronous professional development model targeting multisyllabic reading and spelling. In three Title I elementary schools in the Southeastern United States, 16 educators participated in two implementation cycles. Fidelity was assessed through checklists and daily logs, while contributing factors were analyzed at individual and systemic levels. Findings revealed that while contextual constraints affected fidelity, engagement with professional development and reflective practices supported improvement over time. Furthermore, limited prior training and students’ challenges with decoding strategies affected implementation timing. These insights can strengthen intervention delivery, enhance interpretation of student outcomes, and inform sustainable adoption of evidence-based literacy practices in diverse school settings as fidelity and integrity of implementation are considered.