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Tiered Instruction and Intervention - General Questions

When implementing RTI, is there a recommended ratio of students to teachers at different tiers of intervention?

Response from Amanda VanDerHeyden, Ph.D.:

The feature that distinguishes one tier of intervention from another is intensity. Tier 1 intervention is typical instruction to which all students in the class are exposed (often called universal or core instruction) and is the least intensive. Tier 2 is for children who do not respond successfully to Tier 1 intervention and is more intensive than Tier 1 intervention. Tier 3 is the most intense level of intervention and is for the small number of children who do not respond successfully to intervention at Tiers 1 and 2.


Some features of intervention that can be altered to increase intervention intensity include duration of the intervention, frequency of the intervention, frequency of progress monitoring during intervention, scope of skills addressed during intervention, format of intervention (e.g., small-group versus individual), and use of standard protocol versus individualized functional assessment. Presumably decreasing the student to teacher ratio will increase intensity because it can permit more opportunities for the student to respond and practice the skill, more opportunities for the student to receive individualized feedback about the accuracy of his/her responses, and more individualized adjustment of the instructor’s response tailored to the student’s need (e.g., teacher can briefly reduce task difficulty, re-train a prerequisite skill, provide brief instruction on a new skill, change to fluency-building practice, add incentives, etc based on student performance). Importantly, with intervention implementation, the devil is in the details as they say and the degree to which a lower student to teacher ratio actually or functionally increases intervention intensity depends upon the degree to which the lower student to teacher ratio permits more individualized and higher quality instruction than would be possible in working with a small group of students. Hence, implementers should consider that it is possible to reduce student to teacher ratio and not increase intensity, just as it is possible to increase the duration of intervention and not really increase the intensity of intervention. If intensity is defined as the power or force with which a process operates as estimated by the results that are obtained, then intensity of intervention is evaluated by its capacity to improve learning. More intense interventions are those interventions that have greater capacity to improve learning. While features like student to teacher ratio and duration of intervention are signals that the intervention might be more intensive, it’s really the degree to which these conditions permit more effective, more individualized, and more frequent instructional interactions to occur that define intensity. Implementers should plan for monitoring intervention intensity via use of intervention protocols, frequent student progress monitoring, and direct intervention integrity checks.

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