A teacher establishes red flags--clear and unambiguous warning signals--that enable her to intervene before students fail. Any student who has less than an 80 percent class average or who receives less than 80 percent on a quiz immediately moves into an intervention cycle in which the teacher regularly "checks in" with the student. Interventions include providing a review packet and various instructional supports, requiring student attendance at lunchtime acceleration and remediation sessions, and conferencing with parents. This article addresses how to close the achievement gap for at-risk students through assessment and remedial instruction.