The term direct instruction was first used in 1968, when Science Research Associates published a beginning reading program called DISTAR, authored by Siegfried Engelmann and his colleagues. Since 1968, the use of the term direct instruction has evolved in two main directions: DI and di.
Direct Instruction (DI)
In the 1960's, Zig Engelmann created this explicit, carefully sequenced and scripted model of instruction. Published Direct Instruction programs are based on a landmark empirical research study and numerous follow-up studies over the last thirty years about how children actually learn. Project Follow Through (1967), the largest educational experiment ever conducted, evaluated nine major approaches to educating at-risk students. Only students taught with the Direct Instruction approach consistently outperformed control students on basic, cognitive, and affective measures. Direct Instruction is sometimes referred to as "capital DI."
direct instruction (di)
In his 1976 teacher effectiveness research, Barak Rosenshine gave this term to a set of variables found to be significantly related to student achievement. This set of variables included engaged time, small group instruction, and specific and immediate feedback. This approach is often referred to as "small di."