Browse the glossary below to learn the terms you need to know to successfully implement RTI in your school. This glossary was compiled using the following resources: The RTI Glossary of Terms developed by the IDEA Partnership @ NASDSE, the New Mexico Public Education Department RTI Glossary, and contributions from members of the RTI Action Network Advisory Council.

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Tertiary Levels of Intervention

Interventions that relate directly to an area of need; are supplementary to and are different from primary and secondary interventions; are usually implemented individually or in very small group settings; may be individualized; are often connected to the narrowest tier of a tiered intervention model.

Tiered Instruction

Levels of instructional intensity within a tiered model.

Tiered Model

Common model of three or more tiers that delineate levels of instructional interventions based on student skill need.


Line on a graph that connects data points; compare against aimline to determine responsiveness to intervention.