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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Data Points

Points on a graph that represent student achievement or behavior relative to a specific assessment at a specific time.

Data teams

Teams of educators that are responsible for data analysis and decision making and that function at the level of the district, school, and grade (or content area) as well as across grade levels in the same content area (i.e., vertical teams); they include as members school administrators, school psychologists, grade/content area general educators, various specialists and other behavioral/mental health personnel.

Data-Based/Data-Driven Decision Making

A process of collecting, analyzing, and summarizing information to answer a question and to guide development, implementation, and evaluation of an action. Data-based decision making is continuous and regular, and most importantly linked to educational/socially important questions.

Dependent Variable

Element that may be influenced or modified by some treatment or exposure.

Differentiated Instruction

Process of designing lesson plans that meet the needs of the range of learners; such planning includes learning objectives, grouping practices, teaching methods, varied assignments, and varied materials chosen based on student skill levels, interest levels, and learning preferences; differentiated instruction focuses on instructional strategies, instructional groupings, and an array of materials.


a) Difference between two outcome measures; b) IQ-achievement discrepancy – difference between scores on a norm-referenced intelligence test and a norm-referenced achievement test; c) Difference between pre-test and post-test on a criterion-referenced test.


The over- or under-representation of minority students in special education. In other words, there is a disproportionate number, either a significantly larger or smaller percentage, of students from a specific minority background receiving special education services than the percentage of that minority in the population generally.

Dual Discrepancy

A dual discrepancy occurs when a student’s performance and growth rate are both substantially below performance and growth rate of typical peers.


For the purposes of documenting response to intervention, duration refers to the length (number of minutes) of a session multiplied by the number of sessions per school year. "Sufficient duration" is dependent on a number of factors including the program or strategy being used, the age of the student, and the severity of the deficit involved. Some programs offer guidelines or recommendations for duration and may even limit the number sessions in which a child can participate, believing that a child who does not make adequate gains after the specified amount of time would likely benefit from an alternative intervention.