Ensuring that core instruction is effective for all students is an essential RTI component. RTI assumes that all students have access to highly qualified teachers who recognize the effect of increased student diversity on teaching and learning. Core instruction includes

• Academics—Core program and universal academic interventions for all students.
• Behavior—Classroom management and universal behavioral interventions (preventive and proactive) that are available to all students.

The RTI triangle generally places core instruction at the first tier. Most RTI frameworks assume that the core program is meeting roughly 80 to 90 percent of students' learning and behavioral needs. From an RTI perspective, schools with fewer than 75 percent of students at or above grade level proficiency have a core program problem. Interventions alone will not solve these students' problems. Further, schools must address core program problems or risk having the same percentage of students requiring interventions year after year.