Tier one is the low-risk stage of RTI. This tier is usually whole-class research-based core instruction. Students' progress is monitored through tests, homework assignments, and other measures. If a student is found to be struggling, then they may be moved up to tier two.

Tier two usually involves small group lessons two to three times a week. Although students in tier two are receiving this small group support, they are still receiving tier one support in regular lessons.

The teacher checks the student's skill levels every one to two weeks. If the student is making great progress, they may be moved back to tier one. If the student is still struggling, they may be kept in tier two support, or moved up to tier three. 

Tier three is the most intense level of RTI support and is known as high risk. Small group lessons may still occur in this tier, but individualized lessons are more likely. Students spend time in the general education classroom and resource rooms. In this tier, teachers often check the student's progress to see if the student is progressing. If students improve greatly, they may return to the second tier.