Detailed Notes on Tiers of Intervention in Responsiveness to Intervention
Introduction to Response to Intervention (RTI)
RTI models are gaining traction as an alternative to traditional methods for identifying students with learning disabilities (LD).
A key aspect of RTI is implementing academic interventions in general education and assessing student response.
A crucial question is determining the necessary number of intervention tiers in an RTI model.
This article reviews three RTI studies that explore the tiers of intervention.
Sharon Vaughn and Rollanda O’Connor's studies use the Standard Protocol approach.
David Tilly's study uses the Problem-Solving Model.
The passage of IDEA 2004 emphasized RTI's role in identifying students with LD.
Educators need guidance on practical aspects of intervention methodology when implementing RTI.
Vaughn (2003), O’Connor (2003), and Tilly (2003) address intervention tiers and special education eligibility.
Vaughn and O’Connor use controlled research studies with random assignment, control groups, treatment integrity reviews, and clear parameters for treatment variables duration.
Tilly's paper describes the problem-solving model implementation across almost a quarter of Iowa’s students.
Tilly’s paper resembles a program evaluation report, featuring large sample sizes and professional development for 130+ schools.
The studies align with two popular RTI approaches: standard treatment protocol and the problem-solving model.
Both approaches offer insights into the number of tiers needed for prevention outcomes and LD identification.
Vaughn’s Three-Tier RTI Model for Literacy
Sharon Vaughn's model targets kindergarten through third-grade literacy.
Tier 1: Core reading instruction (90 min/day) for all general education students.
Focuses on research-based practices: phonemic awareness, alphabetic understanding, fluency, vocabulary, and comprehension.
Student performance is monitored three times per year.
Emphasizes ongoing, scientifically-based professional development for school staff.
Tier 2: Supplemental reading program (30 min/day).
Students who didn't respond to Tier 1 are recipients, based on early literacy benchmarks.
Delivered by general education, special education, or project staff.
Intervention lasts 10–20 weeks.
Students are randomly assigned to intervention groups.
Progress is monitored twice per month.
Tier 3: More intensive and strategic interventions.
Small groups of three students with one instructor.
Delivered by an intervention specialist from the school or project staff.
Two 30 min sessions per day.
Custom-built sessions tailored to individual needs.
Student performance monitored twice per month.
Interventions can be longer than Tier 2's 10–20 weeks.
O’Connor’s Three-Tier Approach
Rollanda E. O’Connor’s study mirrors Vaughn’s, using a strong experimental research design.
Tier 1: Core reading instruction for all students.
Focuses on ongoing professional development based on scientifically-backed reading interventions related to five major elements.
Student improvement measured three times per year with literacy indicators.
Tier 2: Small group intervention (typically one-to-four students).
Conducted 3 days/week; 15 min for kindergarten, 20–25 min for older students.
Project researcher provides instruction to students not meeting literacy benchmarks in Tier 1.
Designed specifically for the struggling student.
Differs from Vaughn’s: focuses on student weaknesses, and interventions vary from 8 weeks to several years.
Tier 3: Daily intervention by a project researcher in one-to-one or one-to-two settings.
Intended for students not making reading progress commensurate with average readers.
Tilly’s Problem-Solving Model in Iowa (Project HELP)
W. David Tilly III reports on implementing the problem-solving model in Iowa.
Heartland Area Education Agency (AEA) serves about 25% of Iowa’s students; the evaluation includes data from 136 schools.
Heartland AEA evolved from a four-tier to a three-tier system over 10 years.
The three-tier system is central to the Heartland Early Literacy Project (Project HELP), providing data for the paper.
While lacking the experimental design of Vaughn and O’Connor, it featured large sample sizes and evidence of RTI at scale.
Project HELP grew from 36 schools in 1999 to 121 schools by 2003–2004.
Level 1 (Tier 1): Core Instructional Curriculum for all students.
Level 2 (Tier 2): Core Instruction and Supplemental Instructional Resources.
Level 3 (Tier 3): Core Instruction and Intensive Resources.
Emphasizes two assumptions at each level: applied scientific method (problem-solving) and scientifically-based practices during intervention.
Problem-solving questions: (a) What is the problem? (b) Why is it happening? (c) What do we do about it? (d) Is the intervention working?
Scientifically-based practices: curriculum-based measurement, curriculum-based evaluation, functional analysis of behavior and positive behavioral supports, direct instruction, peer-assisted learning strategies, learning strategy instruction, and dynamic indicators of basic early literacy skills.
Includes large-scale screening of all students and a strong professional development component.
Requires monitoring of student performance two or three times per year, focusing on phoneme segmentation, nonsense word fluency, and oral reading fluency.
The duration of individual sessions or the number of sessions was not specified, nor was the size of instructional groupings.
Instruction was provided by different types of teachers in each building.
Common Principles of RTI
The three papers align with the core elements of an RTI model, as outlined in the Common Ground Report (2002) by the National Research Center on Learning Disabilities.
The eight professional groups that contributed to the report:
National Association of School Psychologists
American Speech-Language-Hearing Association
Council for Exceptional Children/Division for Learning Disabilities
International Reading Association
Association for Higher Education and Disability
International Dyslexia Association
Learning Disabilities Association of America
National Center for Learning Disabilities
The group established 14 consensus statements related to identification, eligibility, and intervention.
The models and data from Vaughn, O’Connor, and Tilly are largely consistent with these principles.
Key Consensus Statements and Application to RTI Models
Identification: "Identification should include a student-centered, comprehensive evaluation and problem-solving approach…"
Vaughn, O’Connor, and Tilly all qualify through their multitier design and various assessment types.
Regular Education Responsibility: "Regular education must assume active responsibility for delivery of high-quality instruction…"
All three studies indicate Tier 1 is primarily a general education activity, emphasizing research-based interventions with professional development.
Tier 2 involves both general and special educators, increasing collaboration.
Tier 3 leans toward specialists with experience in intensive interventions.
Eligibility: "The ability–achievement discrepancy formula should not be used for determining eligibility."
The formula is not mentioned in any of the studies.
Comprehensive Evaluation: "Decisions regarding eligibility…must draw from information collected from a comprehensive individual evaluation…"
All three papers use various literacy measures to select students for more intensive instruction.
The evaluation summary report in the RTI model includes detailed descriptions of interventions and student response.
Interdisciplinary Team: "Decisions on eligibility must be made through an interdisciplinary team…"
The papers do not detail the activities of the interdisciplinary team, an area needing more emphasis in future research.
Timely Decisions: "Decisions on eligibility must be made in a timely manner."
Vaughn specifies timelines in Tier 2. O’Connor and Tilly are less specific, an important area for future studies.
Varying Levels of Support: "…a student who has been identified as having a specific learning disability may need different levels of special education…"
The models can be expanded to include special education intervention tiers.
Consensus Statements on intervention
Scientifically Based Practices: "The field should continue to advocate for the use of scientifically based practices…"
All three researchers identify the critical elements of the National Reading Panel as major components of their professional development activities.
Tilly lists eight research-based practices used in Project HELP.
Frequent data collection in Tiers 2 and 3 can examine intervention effectiveness.
Access to Information: "Schools and educators must have access to information about scientifically based practices…"
The researchers have made efforts to incorporate scientifically based practices and provide professional development.
Intensive Instruction: "Students with specific learning disabilities require intensive, iterative (recursive), explicit scientifically based instruction…"
The problem-solving process includes best practice treatments provided with fidelity and monitored frequently.
Staff are trained on progress monitoring and using data to make instructional changes.
Vaughn and O’Connor measure more frequently (twice per month) in Tiers 2 and 3.
Continuum of Intervention Options: "Students with specific learning disabilities require a continuum of intervention options…"
The papers address a continuum of regular education interventions leading up to identification, not the range of special education interventions.
Timely and Matched Interventions: "Interventions must be timely and matched to the specific learning and behavioral needs of the student."
The researchers document the use of timely interventions matched to student needs; student data dictates movement through the continuum.
Vaughn emphasizes 10-week intervals for Tier 2; O’Connor notes Tier 2 interventions range from 8 weeks to years; Tilly does not detail tier duration.
Staff are trained to use data to determine movement through tiers.
O’Connor notes Tier 2 interventions are customized to student weaknesses.
Consistent Implementation: "An intervention is most effective when it is implemented consistently, with fidelity to its design, and at a sufficient level of intensity and duration."
Treatment fidelity is central to Vaughn and O’Connor’s research; Vaughn’s study includes eight validity checks per interventionist; Tilly acknowledges its importance.
Coordination of Regular and Special Education: "Regular and special education must be coordinated…"
All three studies reveal collaboration between regular and special education; professional development includes all staff; school staff cooperated in planning and delivering interventions.
Results of the Three Studies
Vaughn, O’Connor, and Tilly provide results regarding the implementation of RTI.
Outcomes: student performance on early literacy measures across tiers and movement of students through tiers into special education.
Contrasts of Student Performance
Vaughn and O’Connor's studies compare control groups with Tier 1, Tier 2, and Tier 3 interventions.
The studies include control groups, random assignment, measures of student growth (letter naming, phonemic awareness, word identification, fluency, and comprehension).
Vaughn found Tier 1 students made more progress than control students. Students needing both Tier 1 and Tier 2 interventions also made significantly more progress than controls.
O’Connor provides effect sizes. Tier 1 students outscored controls across all measures (effect sizes 0.19 to 0.52, average 0.34). Tier 2 students compared to controls resulted in effect sizes ranging from 0.40 to 0.67, with an average of 0.55. Even greater effect sizes for Tier 2 and 3 students compared to controls.
Tilly studied early literacy growth of students in Tiers 1, 2, and 3. Reports raw scores at the 20th, 50th, and 80th percentile at each school for the beginning, middle, and end of the year. Examined the amount schools changed from Year 1 to Year 2/Year 3.
Effect sizes for phonemic awareness: 0.71 (Year 1 to Year 2) and 1.08 (Year 1 to Year 3). For oral reading fluency: 0.26 (Year 1 to Year 2) and 0.39 (Year 1 to Year 3).
Movement of Students Through Tiers
The impact of the multitier RTI model can be evaluated by examining placement outcomes.
Vaughn studied 45 second-grade students in Tier 2. Some students showed enough progress to exit early (10 weeks), midterm exit (20 weeks), late exit (30 weeks), and 11 students (24.4%) did not meet success criteria.
Vaughn theorized that at-risk students need at least 20 weeks of intervention to determine non-responsiveness.
For O’Connor, half of Tier 2 students did not make good reading progress. In Tier 3, almost 40% maintained average performance without additional help. Control group: 15% to special education. Tier 1 only: 12% to special education. Tiers 1, 2, and 3: 8% to special education.
Tilly reviewed placement rates in special education in schools with the longest implementation of Project HELP (n = 36). Compared placement rates from the 3-year period prior to implementation of HELP to the 4-year period after implementation. Special education placements decreased at all grade levels: 39% in kindergarten, 32% in first grade, 21% in second grade, and 19% in third grade.
Tables summarizing Results
Table 1: Results for Contrasts of Student Performance
Table 2: Results for Movement of Students Through Tiers
Summary of Findings
The three papers tell us about the number of tiers needed within RTI to achieve acceptable prevention outcomes and acceptable patterns of LD identification.
How Many Tiers Are Needed for Acceptable Prevention Outcomes?
Tier 1 data shows student gains. Moderate effect sizes.
Tier 2 shows students did significantly better than controls. Moderate effect sizes (about 0.55). 50% to 75% of students responded to instruction.
Tier 3 provided best data for acceptable prevention outcomes. Gains of students receiving Tier 2 and 3 were significantly greater than controls. Higher effect sizes than Tier 1 and 2. Close to 40% of Tier 3 students made satisfactory gains. 92% of students responded to either Tier 1, 2, or 3 interventions.
How Many Tiers Are Needed For Acceptable Patterns of LD Identification?
Little data supported Tier 1 alone to determining special education eligibility.
25% to 50% of Tier 2 students were nonresponders.
Tier 3 data from one study showed 7 out of 10 Tier 3 students entering special education. 6% of student population participating in the three-tier model was eligible for LD services.
Conclusion
The Vaughn, O’Connor, and Tilly studies provide positive outcomes for the three-tier approach to response to intervention.
The RTI models had a considerable impact on elementary student achievement in reading.
Future research should consider other academic domains, grade level of students, and scalability.
The studies of Vaughn, O’Connor, and Tilly describe promising approaches to RTI.
Introduction to Response to Intervention (RTI)
RTI models are gaining traction as an alternative to traditional methods for identifying students with learning disabilities (LD).
A key aspect of RTI is implementing academic interventions in general education and assessing student response; this involves systematic monitoring of student progress and adjusting interventions based on performance data.
A crucial question is determining the necessary number of intervention tiers in an RTI model; each tier should offer progressively intensive support.
This article reviews three RTI studies that explore the tiers of intervention.
Sharon Vaughn and Rollanda O’Connor's studies use the Standard Protocol approach, ensuring consistent intervention delivery across students.
David Tilly's study uses the Problem-Solving Model, which emphasizes individualized assessment and intervention planning.
The passage of IDEA 2004 emphasized RTI's role in identifying students with LD; its use is crucial for making informed decisions about special education eligibility.
Educators need guidance on practical aspects of intervention methodology when implementing RTI, including how to select evidence-based interventions and monitor treatment fidelity.
Vaughn (2003), O’Connor (2003), and Tilly (2003) address intervention tiers and special education eligibility. Each study provides unique insights into how RTI can be effectively implemented.
Vaughn and O’Connor use controlled research studies with random assignment, control groups, treatment integrity reviews, and clear parameters for treatment variables duration;
these rigorous designs enhance the validity and reliability of findings.Tilly's paper describes the problem-solving model implementation across almost a quarter of Iowa’s students, providing a large-scale perspective on RTI implementation.
Tilly’s paper resembles a program evaluation report, featuring large sample sizes and professional development for 130+ schools, indicating a substantial investment in RTI implementation.
The studies align with two popular RTI approaches: standard treatment protocol and the problem-solving model.
Both approaches offer insights into the number of tiers needed for prevention outcomes and LD identification. Further, they highlight the importance of data-based decision-making.
Vaughn’s Three-Tier RTI Model for Literacy
Sharon Vaughn's model targets kindergarten through third-grade literacy.
Tier 1: Core reading instruction (90 min/day) for all general education students.
Focuses on research-based practices: phonemic awareness, alphabetic understanding, fluency, vocabulary, and comprehension. These are the five pillars of reading instruction.
Student performance is monitored three times per year. Progress is tracked using universal screening measures to identify students at risk.
Emphasizes ongoing, scientifically-based professional development for school staff. Teachers receive training in effective reading instruction strategies.
Tier 2: Supplemental reading program (30 min/day).
Students who didn't respond to Tier 1 are recipients, based on early literacy benchmarks. These benchmarks help identify students needing additional support.
Delivered by general education, special education, or project staff. Collaboration among staff is crucial for effective implementation.
Intervention lasts 10–20 weeks. This duration allows sufficient time to assess student response to the intervention.
Students are randomly assigned to intervention groups to ensure unbiased evaluation.
Progress is monitored twice per month using progress monitoring tools. This frequent monitoring helps in making timely instructional adjustments.
Tier 3: More intensive and strategic interventions.
Small groups of three students with one instructor ensure individualized attention.
Delivered by an intervention specialist from the school or project staff. Specialists provide targeted support based on student needs.
Two 30 min sessions per day offer additional instructional time.
Custom-built sessions tailored to individual needs. Interventions are designed to address specific skill deficits.
Student performance monitored twice per month to track progress and adjust interventions.
Interventions can be longer than Tier 2's 10–20 weeks, depending on student response.
O’Connor’s Three-Tier Approach
Rollanda E. O’Connor’s study mirrors Vaughn’s, using a strong experimental research design.
Tier 1: Core reading instruction for all students.
Focuses on ongoing professional development based on scientifically-backed reading interventions related to five major elements. This ensures teachers are equipped with effective strategies.
Student improvement measured three times per year with literacy indicators. These indicators provide data on overall student performance.
Tier 2: Small group intervention (typically one-to-four students).
Conducted 3 days/week; 15 min for kindergarten, 20–25 min for older students to provide targeted support.
Project researcher provides instruction to students not meeting literacy benchmarks in Tier 1. Researchers bring expertise in implementing interventions.
Designed specifically for the struggling student, focusing on individual needs.
Differs from Vaughn’s: focuses on student weaknesses, and interventions vary from 8 weeks to several years, allowing for flexible support.
Tier 3: Daily intervention by a project researcher in one-to-one or one-to-two settings.
Intended for students not making reading progress commensurate with average readers, providing intensive support.
Tilly’s Problem-Solving Model in Iowa (Project HELP)
W. David Tilly III reports on implementing the problem-solving model in Iowa.
Heartland Area Education Agency (AEA) serves about 25% of Iowa’s students; the evaluation includes data from 136 schools, representing a large-scale implementation.
Heartland AEA evolved from a four-tier to a three-tier system over 10 years.
The three-tier system is central to the Heartland Early Literacy Project (Project HELP), providing data for the paper. This project is a key component of Iowa's RTI efforts.
While lacking the experimental design of Vaughn and O’Connor, it featured large sample sizes and evidence of RTI at scale.
Project HELP grew from 36 schools in 1999 to 121 schools by 2003–2004, indicating increasing adoption of the model.
Level 1 (Tier 1): Core Instructional Curriculum for all students.
Level 2 (Tier 2): Core Instruction and Supplemental Instructional Resources.
Level 3 (Tier 3): Core Instruction and Intensive Resources.
Emphasizes two assumptions at each level: applied scientific method (problem-solving) and scientifically-based practices during intervention. These assumptions guide the implementation of RTI.
Problem-solving questions: (a) What is the problem? (b) Why is it happening? (c) What do we do about it? (d) Is the intervention working? These questions drive the problem-solving process.
Scientifically-based practices: curriculum-based measurement, curriculum-based evaluation, functional analysis of behavior and positive behavioral supports, direct instruction, peer-assisted learning strategies, learning strategy instruction, and dynamic indicators of basic early literacy skills. These practices are integral to effective interventions.
Includes large-scale screening of all students and a strong professional development component, ensuring comprehensive support.
Requires monitoring of student performance two or three times per year, focusing on phoneme segmentation, nonsense word fluency, and oral reading fluency. These measures assess foundational literacy skills.
The duration of individual sessions or the number of sessions was not specified, nor was the size of instructional groupings, indicating a need for further detail.
Instruction was provided by different types of teachers in each building, highlighting the importance of collaboration.
Common Principles of RTI
The three papers align with the core elements of an RTI model, as outlined in the Common Ground Report (2002) by the National Research Center on Learning Disabilities.
The eight professional groups that contributed to the report:
National Association of School Psychologists
American Speech-Language-Hearing Association
Council for Exceptional Children/Division for Learning Disabilities
International Reading Association
Association for Higher Education and Disability
International Dyslexia Association
Learning Disabilities Association of America
National Center for Learning Disabilities
The group established 14 consensus statements related to identification, eligibility, and intervention. These statements provide a framework for RTI implementation.
The models and data from Vaughn, O’Connor, and Tilly are largely consistent with these principles, reinforcing the validity of their findings.
Key Consensus Statements and Application to RTI Models
Identification: "Identification should include a student-centered, comprehensive evaluation and problem-solving approach…"
Vaughn, O’Connor, and Tilly all qualify through their multitier design and various assessment types. Their approaches ensure thorough student evaluation.
Regular Education Responsibility: "Regular education must assume active responsibility for delivery of high-quality instruction…"
All three studies indicate Tier 1 is primarily a general education activity, emphasizing research-based interventions with professional development. This highlights the role of general education in RTI.
Tier 2 involves both general and special educators, increasing collaboration. This collaboration enhances support for struggling students.
Tier 3 leans toward specialists with experience in intensive interventions, ensuring targeted support.
Eligibility: "The ability–achievement discrepancy formula should not be used for determining eligibility."
The formula is not mentioned in any of the studies.
Comprehensive Evaluation: "Decisions regarding eligibility…must draw from information collected from a comprehensive individual evaluation…"
All three papers use various literacy measures to select students for more intensive instruction. These measures provide data for decision-making.
The evaluation summary report in the RTI model includes detailed descriptions of interventions and student response.
Interdisciplinary Team: "Decisions on eligibility must be made through an interdisciplinary team…"
The papers do not detail the activities of the interdisciplinary team, an area needing more emphasis in future research. This highlights a gap in current research.
Timely Decisions: "Decisions on eligibility must be made in a timely manner."
Vaughn specifies timelines in Tier 2. O’Connor and Tilly are less specific, an important area for future studies. Timeliness is critical for effective intervention.
Varying Levels of Support: "…a student who has been identified as having a specific learning disability may need different levels of special education…"
The models can be expanded to include special education intervention tiers, providing a continuum of support.
Consensus Statements on intervention
Scientifically Based Practices: "The field should continue to advocate for the use of scientifically based practices…"
All three researchers identify the critical elements of the National Reading Panel as major components of their professional development activities. The NRP's findings inform effective reading instruction.
Tilly lists eight research-based practices used in Project HELP. These practices are grounded in empirical evidence.
Frequent data collection in Tiers 2 and 3 can examine intervention effectiveness. Data informs instructional decisions.
Access to Information: "Schools and educators must have access to information about scientifically based practices…"
The researchers have made efforts to incorporate scientifically based practices and provide professional development, ensuring effective implementation.
Intensive Instruction: "Students with specific learning disabilities require intensive, iterative (recursive), explicit scientifically based instruction…"
The problem-solving process includes best practice treatments provided with fidelity and monitored frequently. Fidelity ensures interventions are implemented as designed.
Staff are trained on progress monitoring and using data to make instructional changes. Training enhances data-based decision-making.
Vaughn and O’Connor measure more frequently (twice per month) in Tiers 2 and 3, allowing for timely adjustments.
Continuum of Intervention Options: "Students with specific learning disabilities require a continuum of intervention options…"
The papers address a continuum of regular education interventions leading up to identification, not the range of special education interventions. This highlights a gap in the current models.
Timely and Matched Interventions: "Interventions must be timely and matched to the specific learning and behavioral needs of the student."
The researchers document the use of timely interventions matched to student needs; student data dictates movement through the continuum. Data drives decision-making in RTI.
Vaughn emphasizes 10-week intervals for Tier 2; O’Connor notes Tier 2 interventions range from 8 weeks to years; Tilly does not detail tier duration. Consistency in duration is important.
Staff are trained to use data to determine movement through tiers. Training enhances the effectiveness of tier transitions.
O’Connor notes Tier 2 interventions are customized to student weaknesses, ensuring targeted support.
Consistent Implementation: "An intervention is most effective when it is implemented consistently, with fidelity to its design, and at a sufficient level of intensity and duration."
Treatment fidelity is central to Vaughn and O’Connor’s research; Vaughn’s study includes eight validity checks per interventionist; Tilly acknowledges its importance. Fidelity ensures interventions are implemented as intended.
Coordination of Regular and Special Education: "Regular and special education must be coordinated…"
All three studies reveal collaboration between regular and special education; professional development includes all staff; school staff cooperated in planning and delivering interventions. Collaboration is essential for effective RTI implementation.
Results of the Three Studies
Vaughn, O’Connor, and Tilly provide results regarding the implementation of RTI.
Outcomes: student performance on early literacy measures across tiers and movement of students through tiers into special education. These outcomes provide insights into RTI effectiveness.
Contrasts of Student Performance
Vaughn and O’Connor's studies compare control groups with Tier 1, Tier 2, and Tier 3 interventions.
The studies include control groups, random assignment, measures of student growth (letter naming, phonemic awareness, word identification, fluency, and comprehension).
Vaughn found Tier 1 students made more progress than control students. Students needing both Tier 1 and Tier 2 interventions also made significantly more progress than controls.
O’Connor provides effect sizes. Tier 1 students outscored controls across all measures (effect sizes 0.19 to 0.52, average 0.34). Tier 2 students compared to controls resulted in effect sizes ranging from 0.40 to 0.67, with an average of 0.55. Even greater effect sizes for Tier 2 and 3 students compared to controls.
Tilly studied early literacy growth of students in Tiers 1, 2, and 3. Reports raw scores at the 20th, 50th, and 80th percentile at each school for the beginning, middle, and end of the year. Examined the amount schools changed from Year 1 to Year 2/Year 3.
Effect sizes for phonemic awareness: 0.71 (Year 1 to Year 2) and 1.08 (Year 1 to Year 3). For oral reading fluency: 0.26 (Year 1 to Year 2) and 0.39 (Year 1 to Year 3).
Movement of Students Through Tiers
The impact of the multitier RTI model can be evaluated by examining placement outcomes.
Vaughn studied 45 second-grade students in Tier 2. Some students showed enough progress to exit early (10 weeks), midterm exit (20 weeks), late exit (30 weeks), and 11 students (24.4%) did not meet success criteria.
Vaughn theorized that at-risk students need at least 20 weeks of intervention to determine non-responsiveness.
For O’Connor, half of Tier 2 students did not make good reading progress. In Tier 3, almost 40% maintained average performance without additional help. Control group: 15% to special education. Tier 1 only: 12% to special education. Tiers 1, 2, and 3: 8% to special education.
Tilly reviewed placement rates in special education in schools with the longest implementation of Project HELP (n = 36). Compared placement rates from the 3-year period prior to implementation of HELP to the 4-year period after implementation. Special education placements decreased at all grade levels: 39% in kindergarten, 32% in first grade, 21% in second grade, and 19% in third grade.
Tables summarizing Results
Table 1: Results for Contrasts of Student Performance
Table 2: Results for Movement of Students Through Tiers
Summary of Findings
The three papers tell us about the number of tiers needed within RTI to achieve acceptable prevention outcomes and acceptable patterns of LD identification.
How Many Tiers Are Needed for Acceptable Prevention Outcomes?
Tier 1 data shows student gains. Moderate effect sizes.
Tier 2 shows students did significantly better than controls. Moderate effect sizes (about 0.55). 50% to 75% of students responded to instruction.
Tier 3 provided best data for acceptable prevention outcomes. Gains of students receiving Tier 2 and 3 were significantly greater than controls. Higher effect sizes than Tier 1 and 2. Close to 40% of Tier 3 students made satisfactory gains. 92% of students responded to either Tier 1, 2, or 3 interventions.
How Many Tiers Are Needed For Acceptable Patterns of LD Identification?
Little data supported Tier 1 alone to determining special education eligibility.
25% to 50% of Tier 2 students were nonresponders.
Tier 3 data from one study showed 7 out of 10 Tier 3 students entering special education. 6% of student population participating in the three-tier model was eligible for LD services.
Conclusion
The Vaughn, O’Connor, and Tilly studies provide positive outcomes for the three-tier approach to response to intervention.
The RTI models had a considerable impact on elementary student achievement in reading.
Future research should consider other academic domains, grade level of students, and scalability. More research is needed to generalize findings.
The studies of Vaughn, O’Connor, and Tilly describe promising approaches to RTI.