What is Response to Intervention (RtI)?
In education, Response To Intervention (commonly abbreviated RTI or RtI) is a method of academic and behavior intervention used in the United States designed to provide early, effective assistance to children who are having difficulty.

Response to Intervention was also designed to function as a data-based process of diagnosing learning disabilities. This method can be used at the group and individual level. The RtI method has been developed by researchers as an alternative to identifying learning disabilities with the ability achievement discrepancy model, which requires children to exhibit a severe discrepancy between their IQ and academic achievement as measured by standardized tests.

RtI seeks to prevent academic failure through early intervention, frequent progress measurement, and increasingly intensive research-based instructional interventions for children who continue to have difficulty. RtI may assist schools in avoiding the so-called "wait-to-fail" method by providing intervention as soon as children exhibit difficulty.

RtI Law as Related to Special Education
IDEA 2004 - When Congress reauthorized IDEA, they changed the law about how to identify children with specific learning disabilities. IDEA 2004 says schools “shall not be required to take into consideration whether a child has a severe discrepancy between achievement and intellectual ability in oral expression, listening comprehension, written expression, basic reading skill, reading comprehension, mathematical calculation, or mathematical reasoning.” (Section 1414 (b))

IDEA 2004 states, “In determining whether a child has a specific learning disability, a local educational agency may use a process that determines if the child responds to scientific, research-based intervention…” (Section 1414(b)(6)(B)). According to the IDEA 2004 regulations, States “may prohibit the use of a severe discrepancy between intellectual ability and achievement,” and “must permit the use of a process that determines if the child respond to scientific, research-based intervention as part of the evaluation procedures,” and “may permit the use of other alternative research-based procedures for determining whether a child has a specific learning disability…”

Frequently Used Words and Terms
Progress monitoring: A scientifically based practice used to assess students’ academic performance and evaluate the effectiveness of instruction. Progress monitoring can be implemented with individual students or an entire class. 

Curriculum-based measurement (CBM): Tools for measuring student competency and progress in the basic skill areas of reading fluency, spell-ing, mathematics and written language.

Scientific, research-based instruction: Curriculum and educational interventions that are research-based and have been proven to be effective for most students.

Universal screening: A step taken by school personnel early in the school year to determine which students are "at risk" for not meeting grade level standards. Universal screening can be accomplished by reviewing a student's recent performance on state or district tests or by administering an academic screening to all students in a given grade. Students whose scores on the screening fall below a certain cut-off point are identified as needing continued progress monitoring and possibly more intensive interventions.

Fidelity: The degree to which some-thing is carried out as designed, intended, or planned.

Three-Tier Model
Tier I—Provide quality classroom instruction for all students.
• At least a 90 minute literacy block
• Academic engagement of All students
• Explicit, systematic instruction
• Multiple opportunities to respond to instruction
• Immediate corrective feedback & practice of new skills
• Cumulative review of previously taught skills 

Tier II— Provide supplemental intervention and progress-monitor.
• These are provided in addition to Tier 1 instruction
• May go beyond classroom instruction
• Provided in small group or one-to-one
• Systematic, integrated instruction
• Provided by trained persons
• Frequent, intense
• Measuring progress related to the curriculum

Tier III—Intensify instruction and progress monitor more frequently.
• These are provided in addition to Tier 1 instruction
• More intensive, explicit, systematic than Tier 2.
• Opportunity to narrow focus on specific skill deficiencies
• Responsive to individual student needs in terms of number of hours, skills focus.
• Accelerate student learning to close the knowledge gap between students and grade - level peers.