The Whole School Intervention aproach (WSI) conceptualises literacy and numeracy intervention within 3 layers.
Layer 1: WSI action at the intervention points of curriculum design, pedagogical practices and quality assessment that is responsive to patterns of underachievement in school data.
Layer 2: Targeted group interventions for particular cohorts who have not responded to the layer 1 intervention. Layer 2 interventions are designed to assist identified students in meeting age cohort expectations.
Layer 3: Intensive interventions (usually involving specialists) for students who have not responded to layers 1 and 2 interventions in meeting age cohort expectations.