Direct Instruction model. Developed by Siegfried Engelmann and Wesley Becker of the University of Oregon, direct instruction is scripted and specifies precisely what the teacher says and what the students' responses should be. Moreover, the program designers carefully sequenced the instruction so that students do not progress to higher-order skills unless they have mastered prerequisite basic skills. There is a high degree of interaction between teachers and students so the teacher may receive continuous feedback about how well the students are doing, and adjusts instruction accordingly. The program makes a specific distinction between on-task and off-task behavior: instruction is arranged so that students are fully engaged in learning (via frequent checking for understanding and praises by the teacher) the majority of the time. According to the program sponsors, anything presumed to be learned by students must first be taught by the teacher.