Follow Through
Overall, the only model that had a consistently positive effect on all three aspects of learning was Direct Instruction. The winner was clear. Given the dramatic learning and achievement outcomes in basic skills, cognitive skills and self-esteem of this large scale study, one would have expected that the United States Office of Education would have strongly endorsed and supported the use of Direct Instruction as the model of choice. But the support and adoption decisions seemed to be contrary to the learning outcomes (See Watkins (1988) for an extensive discussion.)

"The results make a mockery of current reforms, because Follow Through clearly showed that some approaches work well and some flop; however, the ones that flopped the most emphatically are still alive today and still promoted vehemently by teachers' groups like the International Reading Association, the National Council of Teachers of English, and the National Council of Teachers of Mathematics. The approaches that did well were roughly the opposite of the romantic notions and theories espoused by these groups. The better performing sponsors presented highly structured instruction that had tight teacher-performance requirements and practices that are 'behavioral'." Englemann, 1992, pp. 4-5)

Why? It would appear that Direct Instruction was not endorsed or supported because the theory and methods espoused by Engelmann were inconsistent with the dominant thinking of American educators. In describing the rejection of Direct Instruction by the educational establishment, the web site of the American Federation of Teachers (American Federation of Teachers, 1998) asserts that Engelmann's programs were criticized for being too rigid and for emphasizing basic skills. The outcome data were discredited and ignored. Schools of Education in universities, boards of education, the Ford Foundation and commercial publishers argued against the research and the data, and they won. Opinion triumphed over data (Engelmann, 1992; Adams & Engelmann, 1996)


https://psych.athabascau.ca/open/engelmann/direct-evid.php