In the RTI process, service delivery is typically divided into three levels (tiers) of support, with the intensity of interventions increasing with each level. Tier 1 is focused specifically within the core curriculum, with instruction and interventions targeting all students. Approximately 80% to 85% of the general student body should be able to meet grade level norms without additional assistance beyond the first tier. Students who consistently do not perform within the expected level of performance through Tier 1 instruction are then provided with additional supplementary interventions at Tier 2, which typically involves small group instruction. Approximately 3% to 6% of students will continue to have difficulties after Tier 2 interventions; these students will then receive Tier 3 intervention services, which is the most intense level of intervention (often one-on-one) provided in the regular education environment. Through RTI, educators can get enough evidence-based data to eliminate the possibility that the poor of academic performance is due to the inadequate instruction. Therefore, RTI is a more powerful process to identify whether the students have learning disability. As RTI is a regular education initiative, all three tiers of services are intended to be provided as supplements to, not replacements for, the regular education curriculum; there are some, however, who view Tier 3 as special education.