Levels of Intervention and Evidence

Levels of Intervention and Evidence

It is important that the instructional practices and interventions delivered within a school’s multi-tiered system of support (MTSS) be grounded in evidence. However, the “practice” that happens within each tier is different; therefore, the type of evidence that is required for each tier also must be different. A useful way to think about evidence-based practices in MTSS is to think about levels of evidence that vary and correspond to the different levels of intervention intensity at each tier.

In the tables below, find resources to support the selection and evaluation of Tier 1, Tier 2, and Tier 3 or intensive interventions.

Tier 1

Comprehensive, research-based curriculum, delivered class-wide to all students. “Evidence-based” at Tier 1 means that the curriculum includes comprehensive coverage of core content that is aligned to grade-level standards and that the instructional strategies and practices used to deliver the curriculum have evidence of efficacy.

Tier 2 (Validated Intervention Program)

Standardized, targeted small-group instruction using a validated intervention program. “Evidence-based” at Tier 2 means that the intervention program has been demonstrated through rigorous research to have a positive impact on target outcomes for students at risk, when delivered with fidelity.

Intensive Intervention (Tier 3)

Individualized intervention, based on frequent and in-depth analysis of student data. “Evidence-based” at Tier 3 means that the interventionist is following the data-based individualization (DBI) process with fidelity, making iterative adaptations as needed to an intervention platform, using his or her clinical judgment and expertise based on analysis of student data.

Related Resources


What Counts as Evidence? Making Decisions for Instruction and Intervention within a Multi-Tiered System of Support


Standards-Relevant Instruction & Multi-Tiered Systems of Support (MTSS) or Response to Intervention (RTI)


Learn more about intensive intervention and the steps in the DBI process

Learn more


Fidelity at Tier 2 is not the same as fidelity at Tier 3. In fact, Tier 3 is the point where practitioners can start to stray from the strict fidelity guidelines associated with Tier 2 interventions. At Tier 3, it is important to maintain fidelity to the individual student plan.