Engelmann's Direct Instruction method and DISTAR
The term Direct Instruction (DI) also applies to a pedagogical model developed by Siegfried Engelmann in 1964 at the University of Illinois Institute for Research on Exceptional Children.DISTAR was a specific direct instruction model also developed by Siegfried Engelmann and Wesley C. Becker. “Project Follow Through,” the largest educational study ever conducted in America, found the DISTAR program to be the most effective model in education. Direct instruction falls under the cognitive theorist's approach to learning.
Another popular direct instruction approach is the Success for All program which uses scripted teaching to instruct elementary children in phonics intensive reading instruction program. What the teacher says is carefully scripted in the program. The program was designed by Johns Hopkins University professor Robert Slavin in the mid 1980s for failing inner city schools in Baltimore. The program requires a dedicated 90 minutes of reading instruction each day in which the teacher must follow a pre-ordained lesson plan that has every minute filled with scripted instruction and specific activities designed to teach reading to every child in the class.
Direct instruction is often contrasted with discovery learning (Tuovinen, & Sweller,1999). While many support discovery learning, because they feel students learn better if they "learn by doing," there is little empirical evidence to support this claim, quite the contrary in fact (Tuovinen and Sweller, 1999). Kirschner, Sweller, and Clark (2006) suggest that fifty years of empirical data does not support those using these unguided methods of instruction. Hmelo-Silver, Duncan, and Chinn (2007)  argue that Kirschner, et al., are conflating several different models of instruction under the term "discovery learning", and that there is, in fact, empirical data that supports the effectiveness of some of these models.
Opponents of direct instruction believe methods of measuring student progress favor skills that are themselves emphasized by direct instruction and deemphasized by discovery education  In addition they suggest aptitude tests focus on students' ability to solve problems, while discovery education emphasizes critical information-seeking and active, fruitful participation in social discourse, goals that cannot be easily measured by traditional empirical methods.
^Effective direct instruction practices in special education settings. Englert, Carol S. Remedial & Special Education, Vol 5(2), Mar-Apr 1984, 38-47
^(Engelmann, S. (2007). Teaching Needy Kids in our Backward System.Eugene, OR: ADI Press.
^Hmelo-Silver, C. E., Duncan, R.G., & Chinn, C.A. (2007) Scaffolding and Achievement in Problem-Based and Inquiry Learning: A Response to Kirschner, Sweller, and Clark (2006), Educational Psychologist, 42(2), 99–107
^Marchand-Martella, & Martella (2002) An Overview and Research Summary of Peer-Delivered Corrective Reading - The Behavior Analyst Today, 3 (2), 214 -234 
Tuovinen, J. E., & Sweller, J. (1999). "A comparison of cognitive load associated with discovery learning and worked examples". Journal of Educational Psychology91 (2): 334–341. doi:10.1037/0022-0622.214.171.1244.