Strategic Intervention Material (SIM) is an instructional material meant to reteach concepts and skills that students were unable to master during regular classroom teaching. A SIM contains several parts: a Guide Card that provides an overview of the lesson; Activity Cards that define tasks for students to practice skills; an Assessment Card to measure skill mastery; an Enrichment Card for additional practice; a Reference Card with extra content; and an Answer Key. Teachers will create SIMs based on their students' least learned skills and be judged on subtasking, congruence, usability, and replicability.