What is MTSS? Multi-Tiered System of Supports Explained (2026 Guide)
MTSS — Multi-Tiered System of Supports — is a data-driven prevention framework that organizes academic, behavioral, and social-emotional supports across three tiers of increasing intensity: universal Tier 1 for all students, targeted Tier 2 for the approximately 10-15% of students needing supplemental help, and intensive Tier 3 for the 1-5% needing individualized intervention. MTSS emerged from the integration of Response to Intervention (RTI, academic) and Positive Behavioral Interventions and Supports (PBIS, behavior) and is embedded in both the Every Student Succeeds Act (20 U.S.C. §6301) and the Individuals with Disabilities Education Act (34 CFR §300.307(a)(2)).
How does MTSS work?
An MTSS system runs on four infrastructure components that repeat in cycles: universal screening three times a year for every student, evidence-based core instruction and behavioral expectations at Tier 1, tiered supplemental intervention delivered in small groups or individually, and curriculum-based progress monitoring whose data determines moves between tiers. Students are not sorted into tiers by diagnosis or category — tiers are determined by responsiveness to instruction, and a student can simultaneously sit at different tiers for reading, math, and behavior.
The foundational four-year cluster-randomized trial of school-wide PBIS by Bradshaw, Waasdorp & Leaf (2015, J Educational Psychology 107(2):546-557) across 37 schools with N=12,344 students produced an office-discipline-referral effect size of d=0.86 and a suspension odds ratio of 0.67 (95% CI [0.51, 0.88]). It is rated "Meets WWC Standards Without Reservations" — the highest designation in the What Works Clearinghouse rubric.
The three tiers
- Tier 1 — Universal (100% of students) — Evidence-based core instruction and schoolwide behavioral expectations. All students receive this layer. Research anticipates that approximately 80% of students will respond adequately at Tier 1 (Fuchs & Fuchs 2006, Reading Research Quarterly 41(1):93-99).
- Tier 2 — Targeted (~10-15% of students) — Small-group supplemental intervention, typically 20-40 minutes three to five times per week. Check-In/Check-Out (CICO), the most widely studied Tier 2 behavior intervention, has a Tau-U effect size of 0.82 (95% CI [0.75, 0.88]) across 46 single-case studies with 233 participants (Drevon, Hixson, Wyse & Rigney 2019, Psychology in the Schools 56(3):393-412).
- Tier 3 — Intensive (~1-5% of students) — Individualized intervention based on a Functional Behavior Assessment (for behavior) or a diagnostic skills assessment (for academics). In behavior, function-matched interventions produce PND=88% vs 68% for non-matched interventions (Gage, Lewis & Stichter 2012, Behavioral Disorders 37(2):55-77).
MTSS vs RTI vs PBIS — how they relate
| Feature | MTSS | RTI | PBIS |
|---|---|---|---|
| Focus | Academic + Behavior + SEL | Academic | Behavior |
| Statutory basis | ESSA; IDEA | IDEA §300.307(a)(2) | IDEA §300.324(a)(2)(i) |
| Tiers | 3 | 3 | 3 |
| Origin | Integration of RTI + PBIS | Fuchs & Fuchs 2006 | Sugai & Horner 2005 |
Expert perspective
"The integrated framework of PBIS ... provides a continuum of behavior support that promotes the social, emotional, and academic success of all students. Its implementation is associated with decreases in problem behavior and increases in academic achievement."
MTSS and IDEA identification
IDEA 2004 (34 CFR §300.307(a)(2)) permits — and in some states requires — the use of a student's response to evidence-based intervention as part of determining Specific Learning Disability eligibility. In those states, RTI data collected across Tiers 1-3 feeds directly into the comprehensive evaluation required before SLD identification. Districts using MTSS as part of identification must ensure that the intervention was delivered with fidelity, that progress was monitored with a validated CBM instrument, and that the duration was sufficient (typically 8-12 weeks at Tier 2 minimum).
Practical caution: the IDEA Child Find mandate (34 CFR §300.111) applies regardless of MTSS status. A district cannot delay evaluation by citing ongoing tier-2 intervention; parents may request evaluation at any time, and the district must respond within the state timeline.
Sustained-implementation research (2025)
Kittelman, McIntosh, Mercer et al. (2025, Exceptional Children 91(2)) tracked 646 schools across 23 states over five years to identify factors predicting sustained Tier 2 and Tier 3 PBIS implementation. Three variables emerged consistently: administrative leadership turnover below one change per three years, annual team fidelity scores at or above 80% on the School-wide Evaluation Tool (SET, κ≥0.82), and ongoing external coaching during the first three years of implementation. Schools lacking any two of the three factors had sustainment rates below 40% by year five.
The disproportionality corollary is equally important: McIntosh, Smolkowski et al. (2021, Educational Researcher 50(6):397-407) found that raw discipline-data dashboards alone produced NULL effects (d=0.04, n.s.) on racial discipline disparities — action-planning with neutralizing-decision-making routines was required.
Implementation roadmap — practical steps
- Select universal screeners for reading, math, and behavior with validated psychometrics (e.g., AIMSweb, FastBridge, DIBELS).
- Define Tier 1 core instruction with reference to What Works Clearinghouse practice guides (IES).
- Establish a multidisciplinary MTSS team that meets at least monthly and reviews screening + progress-monitoring data.
- Implement Tier 2 protocols (e.g., CICO for behavior; systematic phonics groups for reading) with 80%+ fidelity.
- For Tier 3, require a diagnostic academic assessment (or FBA for behavior) before individualization.
- Run decision rules using Fuchs & Fuchs's 4-point rule: four consecutive data points below aim line triggers change.
- Report disaggregated data quarterly to identify disproportionality patterns (IDEA §300.646).
How IncluShift supports MTSS
IncluShift OS aggregates MTSS data across every module in the IncluShift ecosystem: reading fluency and phonics mastery from IncluLiteracy; CRA and PFA progress from IncluMath; regulation check-ins from IncluRegulate; ABC behavior data from IncluManage; and universal screener results from district-level partners. The OS dashboard surfaces MTSS tier distribution by school and grade, flags students approaching decision points under the 4-point rule, and identifies disproportionality patterns under IDEA §300.646. See IncluShift OS and IncluManage.
Key research citations
Bradshaw, Waasdorp & Leaf (2015). Examining variation in the impact of school-wide positive behavioral interventions and supports. J Educational Psychology, 107(2), 546-557. [4-year cluster RCT; d=0.86 ODR]
Fuchs & Fuchs (2006). Introduction to response to intervention. Reading Research Quarterly, 41(1), 93-99. [Foundational RTI framework]
Gersten et al. (2009). Assisting students struggling with mathematics. IES Practice Guide NCEE 2009-4060. [RTI dosage]
Drevon, Hixson, Wyse & Rigney (2019). Check-in/check-out meta-analysis. Psychology in the Schools, 56(3), 393-412. [Tier 2 CICO Tau-U=0.82]
Gage, Lewis & Stichter (2012). FBA-based interventions for students with emotional/behavioral disorders. Behavioral Disorders, 37(2), 55-77. [Function-matched Tier 3]
McIntosh et al. (2021). Effects of equity-focused PBIS on racial discipline disparities. Educational Researcher, 50(6), 397-407. [Disproportionality]
Kittelman et al. (2025). Factors predicting sustained Tier 2/3 PBIS. Exceptional Children, 91(2). [Sustainment research]
Related
This page provides educational information about the MTSS framework; it is not legal or clinical advice. IncluShift products are research-informed adaptive tools; individual products have not been evaluated in their own controlled studies.