Direct Instruction

…Direct instruction (DI), also described as “clear teaching,” refers to a curricula that systematically teaches discrete concepts step by step towards a clearly established academic goal. Students are required to master foundational concepts before moving on. This kind of teaching lends itself to subjects that can be broken down into concrete steps and systematically taught, such as reading, math, grammar, and spelling, so is a strongest fit overall for grade-schooling. …

Why won’t schools use it?