Response to Intervention requires that students be provided with effective instruction. IDEA 2004 offered greater flexibility to schools. Before passage of the law, students had to show a "severe discrepancy" between intellectual ability and achievement in order to considered "learning disabled" for the purposes of special education. This often meant they had to fail before they could be referred.

The purpose of RTI is to prevent failure — and to refer them before they fail. The student must be provided instruction through techniques that are scientifically proven. Their progress must be monitored. Students are referred only if they do not respond to the instruction. If they do not respond, the school does a comprehensive assessment to determine whether or not a learning disability exists.