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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Individuals with Disabilities Education Improvement Act of 2004, also referred to as IDEA 2004

Original passage in 1975; latest reauthorization in 2004; federal statute relative to public education and services to students with disabilities ages 3 through 21.


(as a service delivery model)

Students with identified disabilities are educated with general education age-/grade-level peers.

Independent Variable

Variable that is manipulated or selected by the researcher to determine relationship to a dependent variable; independent variable is the element that someone actively controls/changes (e.g., instructional strategy/intervention), while the dependent variable (e.g., student demonstration of skills) is the element that changes as a result.

Individualized Education Program (IEP)

A written document that is developed, reviewed, and revised in accordance with IDEA 2004 that outlines the special education and related services specifically designed to meet the unique educational needs of a student with a disability.

Integrity of Intervention Implementation

See Fidelity.

Intensive Interventions

Academic and/or behavioral interventions characterized by increased length, frequency, and duration of implementation for students who struggle significantly; often associated with narrowest tier of an RTI tiered model; also referred to as tertiary interventions.


The systematic and explicit instruction provided to accelerate growth in an area of identified need. Interventions are provided by both special and general educators, and are based on training, not titles. They are designed to improve performance relative to a specific, measurable goal. Interventions are based on valid information about current performance, realistic implementation, and include ongoing student progress monitoring.