Response to Intervention or Multi-tier System of Supports is the practice of providing high-quality instruction and interventions matched to student need, monitoring progress frequently to make decisions about changes in instruction or goals and applying child response data to important educational decisions.
NASDSE, RtI: Policy Considerations and Implementation, 2005 (emphasis added)
1.We can effectively teach all children.
3.Use a multi-tier model of support.
4.Use a problem-solving method for decision making.
5.Research-based interventions/instruction to the extent available.