MTSS vs RTI: The Difference and the 3 Tiers Explained

RTI (Response to Intervention) is a tiered model for academic support, mostly reading and math, while MTSS (Multi-Tiered System of Supports) is the broader framework that includes RTI, behavior support (often PBIS) and social-emotional support, all organized into three tiers. In practice, many schools use the terms interchangeably, but the difference matters when you plan supports or talk with families. This guide explains both, walks through each tier, and shows how they connect to special education.

MTSS vs RTI at a glance

The three tiers

Tier 1: core instruction for everyone

Tier 1 is what all students get: high-quality core instruction, clear schoolwide behavior expectations, and a positive classroom climate. A rough rule of thumb is that Tier 1 should meet the needs of about 80% of students. If far fewer are succeeding, the first step is to strengthen core instruction, not to send half the class to intervention.

Tier 1 includes:

• Evidence-based core curriculum
• Differentiated instruction within the classroom
• Universal screening (usually 3 times a year)
• Schoolwide expectations taught and reinforced
• Classroom routines and social-emotional learning

Our guide to differentiation strategies covers many Tier 1 tools.

Tier 2: targeted small-group support

Students who don’t meet benchmarks on screening, or who show early warning signs, get extra support in small groups, usually 3–5 times a week for 20–30 minutes, in addition to core instruction. Often around 10–15% of students receive Tier 2 support.

Examples:

• Small-group phonics or fluency intervention
• Math fact fluency or problem-solving groups
• Check-in/check-out for behavior
• Social skills groups led by a counselor

Progress is monitored every 1–2 weeks.

Tier 3: intensive, individualized support

Students who don’t respond to Tier 2 get more intensive intervention: smaller groups or one-on-one, more time, and instruction tailored to specific skill gaps. Often around 5% of students need Tier 3.

Examples:

• Daily one-on-one reading intervention targeting specific phonics patterns
• An individualized behavior plan based on an FBA (see FBA vs BIP)
• Intensive math intervention with manipulatives and explicit instruction

Progress is monitored weekly. Tier 3 is not the same as special education, although some students in Tier 3 may be referred for an evaluation.

Screening and progress monitoring

Both RTI and MTSS run on data:

• Universal screening: a short assessment for all students, usually fall, winter and spring, to find who may need support.
• Diagnostic assessment: a closer look at specific skills for students flagged by screening.
• Progress monitoring: frequent short probes (for example, weekly oral reading fluency) to see whether an intervention is working.
• Decision rules: agreed-upon guidelines for when to change, intensify or end an intervention.

Keep progress-monitoring probes short and consistent: the same type of probe, at the same level, on a fixed schedule, so the graph actually shows growth.

Where PBIS fits

PBIS is the behavior side of MTSS:

How MTSS connects to special education

MTSS helps identify students who may need more than general education supports. If a student doesn’t respond to well-delivered interventions, the team may refer the student for a special education evaluation. Key points:

• MTSS can’t delay an evaluation. A family can request an evaluation at any time, and the school must respond under IDEA.
• Intervention data helps the evaluation. Records of interventions, duration and progress help the team understand the student’s needs.
• Students with IEPs still participate in MTSS. They receive core instruction and may receive tiered interventions in addition to special education services.
• Some students may qualify for a 504 Plan instead of an IEP. See our IEP vs 504 guide.

What a teacher does in MTSS

• Delivers strong Tier 1 instruction and differentiates within the classroom.
• Reviews screening data with the grade-level team.
• Provides or coordinates Tier 2 groups, depending on the school’s model.
• Collects progress-monitoring data for intervention groups.
• Brings data to problem-solving meetings.
• Communicates with families about interventions and progress.

Example: one student through the tiers

Here’s how MTSS might look for a 2nd grader over a school year.

September (Tier 1). Fall screening shows Leo reading 22 words correct per minute, well below his peers, with many errors on short-vowel words. His teacher keeps strong core phonics instruction and adds a few minutes of targeted practice during centers.

October (Tier 2). The grade-level data team places Leo in a small phonics group four days a week for 30 minutes, focused on short vowels and blends. His progress is checked every other week with a one-minute fluency probe and a short phonics check.

December (review). Leo’s accuracy has improved from 80% to 92%, and his rate is climbing slowly. The team decides to keep Tier 2 and add a short daily repeated-reading routine.

February (Tier 3). Winter screening shows growth, but the gap isn’t closing fast enough. The team intensifies support: daily one-on-one or very small group instruction with a reading specialist, and weekly progress monitoring.

April (decision point). Progress is still limited. The team, including Leo’s parents, discusses a referral for a special education evaluation, using the intervention data to inform it. His parents could have requested an evaluation at any earlier point, too.

Every step is documented: what was done, how often, for how long, and the results. That record is what makes MTSS work.

What the data team meeting looks like

Many schools hold grade-level data meetings every 6–8 weeks. A simple agenda:

1. Review screening or progress data for the whole grade.
2. Check Tier 1 health: what percentage of students are on track? If it’s low, plan a core instruction change.
3. Review Tier 2 and Tier 3 groups: who is responding, who isn’t?
4. Make decisions using agreed rules: continue, intensify, change the intervention, or exit the group.
5. Assign next steps and dates.

Bring your graphs, keep the conversation on data and instruction, and avoid labeling students. “Leo is not yet responding to the blends group” is more useful than “Leo is low.”

Common misconceptions

• “MTSS is a place.” It’s a system of supports, not a room or a program.
• “Tier 3 means special education.” Not necessarily. It means intensive intervention.
• “Students must go through every tier before an evaluation.” No. If a disability is suspected, an evaluation can start at any time.
• “Tier 2 replaces core instruction.” Intervention is in addition to core, not instead of it.

A note on law and privacy

MTSS and RTI practices vary by state and district. This article is general guidance, not legal advice. Intervention records are part of the education record under FERPA. Keep them in official systems and don’t enter student names or identifying details into AI tools.

For more on the IEP cycle, behavior support and data collection, visit our special education teacher resources.