The literature on policy implementation in education has largely concluded that implementing instructional change at a large-scale level is a substantial challenge. But, Rowan and Miller (2007) have shown that reforms using a professional control or a procedural one are more successful than a cultural control. Likewise, some facilitators should be ensured, for example trainers could guide the teachers and give them an easy access to support and equipment needed while they implement the program. It remains unclear, however, what are the processes underlying the greater efficiency of procedural and professional modes of implementation. The major objective of this presentation will be to explore this issue based on the analyses of experimental data of the program implementation. An experimental study was conducted in a sample of secondary schools (n = 19) and classes (n = 82) with the objective to foster the competencies in reading comprehension of 1st year students. Secondary schools were randomly assigned either to the control group or to experimental conditions. Two experimental conditions were created that reflected procedural and/or professional controls. In experimental condition 1, teachers received the structured didactic intervention with a training adapted to its use; in experimental condition 2, teachers received the treatment, adapted training and guidance through coaching sessions.