10.1 Multi-Tiered System of Supports (MTSS / RTI)

10.1 Multi-Tiered System of Supports (MTSS / RTI)

Core Principle: A Multi-Tiered System of Supports (MTSS) is a comprehensive, prevention-focused framework that matches the intensity of instructional and behavioral interventions to students' demonstrated academic needs. Rooted in the Response to Intervention (RTI) provisions of the Individuals with Disabilities Education Act (IDEA 2004) and the Every Student Succeeds Act (ESSA 2015), MTSS replaces the antiquated "wait-to-fail" IQ-achievement discrepancy model with proactive, universal screening, high-quality evidence-based classroom instruction, targeted supplemental support, and rigorous progress monitoring.

On the Foundations of Reading Test (FoRT / Objective 0009), candidates must understand the structural components of the Three-Tier MTSS model, interpret progress monitoring data against goal lines (aimlines), apply the Dual Discrepancy Model to evaluate student responsiveness, ensure intervention fidelity, and execute data-driven decision rules for adjusting instructional intensity.

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The Evolution: From "Wait-to-Fail" to MTSS / RTI

Historically, identifying students with Specific Learning Disabilities (SLD) in reading required documenting a statistically significant discrepancy between a child's general cognitive ability (IQ score) and their academic achievement score on standardized tests. This approach—often termed the IQ-Achievement Discrepancy Model—was fundamentally flawed:

• Delayed Intervention ("Wait-to-Fail"): Discrepancies rarely widened sufficiently until 3rd or 4th grade, missing the critical Kindergarten–Grade 2 neurodevelopmental window when phonological and decoding interventions are most efficacious.
• Assessment Bias: Culturally and linguistically diverse learners and English Learners were disproportionately misdiagnosed or overlooked.
• Confounding Ineffective Teaching with Disability: The model failed to differentiate between students who had true neurobiological reading disabilities (dyslexia) and students who simply suffered from "curriculum casualties" (inadequate, unscientific whole-language instruction).

┌────────────────────────────────────────────────────────────────────────┐
│                     PARADIGM SHIFT IN READING SUPPORT                  │
├───────────────────────────────────┬────────────────────────────────────┤
│  TRADITIONAL DISCREPANCY MODEL    │        MTSS / RTI FRAMEWORK        │
├───────────────────────────────────┼────────────────────────────────────┤
│ • Wait-to-fail approach           │ • Proactive, prevention-oriented   │
│ • Identification in Grades 3–5    │ • Immediate screening in K–Grade 1 │
│ • Relies on cognitive IQ tests    │ • Relies on Curriculum-Based (CBM) │
│ • Static, deficit-based labeling  │ • Dynamic, tiered intensity shifts │
│ • Special Education as 1st rescue │ • General Education tiered support │
└───────────────────────────────────┴────────────────────────────────────┘

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The Three-Tier MTSS Framework

MTSS organizes all reading instruction and intervention into three distinct tiers of increasing intensity, dosage, and precision.

┌────────────────────────────────────────────────────────────────────────┐
│                     THE THREE-TIER MTSS PYRAMID                        │
│                                                                        │
│                            /\                                          │
│                           /  \  TIER 3: Intensive Support (1–5%)       │
│                          /────\  1:1 to 1:3, 45–60 min daily, weekly PM│
│                         /      \                                       │
│                        / TIER 2 \ TIER 2: Targeted Support (10–15%)    │
│                       /──────────\ 3–5 students, 20–30 min, bi-weekly  │
│                      /            \                                    │
│                     /   TIER 1     \ TIER 1: Universal Core (80–85%)   │
│                    /────────────────\ Whole class + differentiated sm. │
│                                       90–120 min daily literacy block  │
└────────────────────────────────────────────────────────────────────────┘

1. Tier 1: Universal Core Instruction (80–85% of Student Population)

• Target Population: All students in the general education classroom. A healthy Tier 1 system successfully brings 80% to 85% of students to grade-level reading benchmark proficiency.
• Curriculum & Pedagogy: Scientifically based, explicit, systematic, and cumulative reading instruction addressing all five pillars of reading (Phonemic Awareness, Phonics, Fluency, Vocabulary, Comprehension). Instruction incorporates universal differentiation via small flexible guided groups and learning stations.
• Dosage & Setting: Delivered during the standard general education literacy block (typically 90 to 120 minutes daily).
• Assessment Schedule: Universal screening administered three times per year (Fall, Winter, Spring / Benchmark testing).
• Instructor: General education classroom teacher.

2. Tier 2: Targeted Supplemental Intervention (10–15% of Student Population)

• Target Population: Students whose universal screening scores fall below benchmark (typically between the 10th and 25th percentiles) or who demonstrate targeted skill deficits in specific domains (e.g., consonant blends, vowel digraphs, multisyllabic decoding).
• Curriculum & Pedagogy: Standardized, evidence-based supplemental intervention programs targeting explicit missing sub-skills. Tier 2 must align with and reinforce Tier 1 core instruction, pre-teaching or reteaching essential concepts.
• Critical Non-Negotiable: Tier 2 intervention is SUPPLEMENTAL; it must NEVER supplant (replace) Tier 1 core instruction. Students must not be pulled from whole-group reading or content-area instruction to receive Tier 2.
• Dosage & Setting: Delivered in small, homogeneous groups of 3 to 5 students, meeting for 20 to 30 minutes, 3 to 5 days per week.
• Assessment Schedule: Progress monitoring conducted bi-weekly (every 2 weeks) using brief, standardized Curriculum-Based Measures (CBMs).
• Instructor: Classroom teacher, reading interventionist, or trained specialist.

3. Tier 3: Intensive Individualized Intervention (1–5% of Student Population)

• Target Population: Students who exhibit severe literacy deficits (below the 10th percentile) or who demonstrate a lack of adequate response to high-fidelity Tier 2 interventions.
• Curriculum & Pedagogy: Highly customized, diagnostic, intensive Structured Literacy programs (e.g., Orton-Gillingham-based multi-sensory curricula). Instruction breaks phonological and morphological skills into micro-steps with high rates of student response, immediate corrective feedback, and extensive multisensory reinforcement.
• Dosage & Setting: Delivered in very small groups of 1 to 3 students (or 1-on-1), meeting for 45 to 60 minutes daily (5 days per week).
• Assessment Schedule: Progress monitoring conducted weekly using standardized CBM probes.
• Instructor: Highly trained reading specialist, licensed literacy interventionist, or special education teacher.

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Master Reference Table: The Three-Tier MTSS Literacy Matrix

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Data-Based Decision Making: The MTSS Problem-Solving Cycle

Data-based individualization (DBI) drives every tier shift within MTSS. Educational decisions are never made on subjective impressions; they rely on psychometrically validated Curriculum-Based Measures (CBMs) such as DIBELS, Acadience Reading, or AIMSweb.

┌────────────────────────────────────────────────────────────────────────┐
│                     DATA-BASED DECISION MAKING CYCLE                   │
│                                                                        │
│  1. Universal Screening (Fall, Winter, Spring)                         │
│     └── Identify students at risk (< 25th percentile)                  │
│                                                                        │
│  2. Diagnostic Assessment                                              │
│     └── Pinpoint exact missing skill (e.g., phonemic blending vs VCe)  │
│                                                                        │
│  3. Set Aimline (Goal Line) & Select Evidence-Based Intervention       │
│     └── Aimline = (End-of-Year Benchmark Goal − Baseline Score) / Wks │
│                                                                        │
│  4. Implement with High Fidelity (min. 6–8 weeks)                      │
│     └── Maintain dosage, group size, and scripted protocol fidelity    │
│                                                                        │
│  5. Progress Monitor & Plot Trendline                                  │
│     └── Bi-weekly (Tier 2) or Weekly (Tier 3) CBM probes               │
│                                                                        │
│  6. Apply Decision Rules (e.g., 4-Point Rule / Trendline Slope)        │
│     ├── Above Aimline: Fade intervention / return to Tier 1            │
│     ├── Along Aimline: Maintain current intervention until benchmark   │
│     └── Below Aimline: Modify dosage/strategy or intensify to Tier 3   │
└────────────────────────────────────────────────────────────────────────┘

Constructing the Aimline (Goal Line)

An Aimline represents the expected trajectory of student growth from their baseline score to the target benchmark score across a specified time period (e.g., 10–12 weeks of intervention).

$\text{Aimline Slope (Rate of Improvement / ROI)} = \frac{\text{Target Benchmark Score} - \text{Baseline Score}}{\text{Number of Weeks of Intervention}}$

• Example: A Grade 2 student scores 15 Words Correct Per Minute (WCPM) on an Oral Reading Fluency baseline screener in September. The Grade 2 mid-year benchmark target at Week 12 is 51 WCPM. $\text{Target ROI} = \frac{51 - 15}{12} = \frac{36}{12} = 3.0 \text{ WCPM per week}$ The teacher plots a straight line on the CBM progress chart connecting (Week 0, 15) to (Week 12, 51).

The 4-Point Rule & Trendline Analysis

Teachers evaluate student progress by comparing the student's actual trendline (or consecutive data points) against the plotted aimline:

1. Four Points Above Aimline: If 4 consecutive progress monitoring data points rise consistently above the aimline, the student is accelerating faster than expected.
   • Decision Rule: Fade support or celebrate goal mastery and transition the student back to Tier 1 core monitoring.
2. Four Points Hovering Along Aimline: If data points cluster along the aimline, the student is making adequate progress at the desired rate of improvement.
   • Decision Rule: Maintain the current intervention protocol until the benchmark goal is achieved.
3. Four Points Below Aimline: If 4 consecutive data points fall below the aimline (or if the trendline slope is significantly flatter than the aimline), the current intervention is failing to close the achievement gap.
   • Decision Rule: Modify or Intensify. Before changing tiers, verify intervention fidelity. If fidelity is confirmed, alter the instructional variable (reduce group size from 5 to 3, increase daily minutes from 20 to 30, change the instructional strategy, or advance to Tier 3).

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The Dual Discrepancy Model

A cornerstone concept on the FoRT is the Dual Discrepancy Model used to identify true non-responsiveness and potential Specific Learning Disabilities (SLD):

┌────────────────────────────────────────────────────────────────────────┐
│                     THE DUAL DISCREPANCY MODEL                         │
├────────────────────────────────────────────────────────────────────────┤
│  A student is identified as exhibiting a lack of response ONLY if      │
│  they demonstrate BOTH discrepancies simultaneously:                   │
│                                                                        │
│  1. PERFORMANCE LEVEL DISCREPANCY:                                     │
│     The student's absolute score remains substantially below grade-   │
│     level benchmark expectations (e.g., < 10th percentile).           │
│                               AND                                      │
│  2. RATE OF IMPROVEMENT (SLOPE) DISCREPANCY:                           │
│     The student's rate of learning (growth slope over time) is         │
│     significantly flatter than that of peers receiving the identical   │
│     high-fidelity tier intervention.                                   │
└────────────────────────────────────────────────────────────────────────┘

• Why Dual Discrepancy Matters: A student who enters Tier 2 with very low baseline skills (level discrepancy) but exhibits a rapid, steep growth slope when provided explicit instruction is responsive—they simply need more time to catch up. Conversely, a student with both low initial performance and a flat growth trajectory despite high-fidelity intervention exhibits the dual discrepancy indicative of an intrinsic learning disability.

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Intervention Fidelity: The Prerequisite for Tier Escalation

Before any student can be referred for special education evaluation under IDEA or moved to Tier 3, the school must verify Intervention Fidelity (Treatment Integrity):

• Definition: The degree to which an intervention is implemented exactly as planned, designed, and researched.
• Five Dimensions of Fidelity:
  1. Adherence: Were all curriculum components and scripted routines delivered as designed?
  2. Dosage (Exposure): Did the student receive the prescribed number of minutes and sessions per week without unexcused cancellations?
  3. Quality of Delivery: Did the interventionist employ explicit modeling, appropriate pacing, and immediate corrective feedback?
  4. Participant Responsiveness: Was the student actively engaged and completing the response tasks?
  5. Differentiation: Was the intervention kept distinct from core classroom teaching?

FoRT Exam Rule: If progress monitoring data shows lack of growth, but the fidelity checklist reveals the reading specialist only met with the group 2 days a week instead of 5, the team cannot conclude the student has a disability or escalate to Tier 3. They must first restore implementation fidelity.