Core Instruction is instruction provided to all students, and is typically guided by a comprehensive core reading program. Part of core instruction is typically provided to the class as a whole, and part is provided during the small group, differentiated instruction period. Although instruction is differentiated by student need during the small group period, materials and lesson procedures from the core program can frequently be used to provide reteaching, or additional teaching to students according to their needs.

Supplemental Instruction is instruction that goes beyond that provided by the comprehensive core program because the core program does not provide enough instruction or practice in a key area to meet the needs of the students in a particular classroom or school. For example, teachers in a school may observe that their comprehensive core program does not provide enough instruction in vocabulary or phonics to adequately meet the needs of the majority of their students. Selection and implementation of a supplemental program in these areas can strengthen the initial instruction and practice provided to all students.

Intervention is the practice of providing scientifically-based, high-quality instruction and progress monitoring to students who are below proficient in reading. Intervention is provided with intensity that is matched to student need. This involves more time daily, above and beyond 90+ minutes of universal (Tier 1 or core) instruction, which is focused on the specific needs of the student as identified by a diagnostic measure. Instruction can be intensified in three ways: (1) more time, (2) more targeted instruction, and (3) smaller group size.

27J Curricular Frames