centralized school registry compiling the information of all new students enrolled in EMS. Due to teachers’ limited availability to participate as tutors, the math tutoring could not start during the first semester, therefore displaying an even lower participation or attendance rate (very close to zero).

2. _The original project design did not include a communication strategy_ . There was a substantial level of confusion regarding the program’s objectives and content among principals, teachers and students. Lack of information about the program’s objective and limited familiarity with counselling and psychological support were quickly filled by stigma, labeling PODER as a program to help “problem students”. Stigmatization was a serious problem affecting attendance rates and the ultimate effects of the program.

3. _Use of out-of-school hours_ . The CBT workshops and math tutoring were planned to be held during out-of-school hours. This was particularly challenging for students who had to arrive earlier at school or stay longer since many of the students in our sample, especially those in the afternoon shift, combine school with work.

4. _Lack of incentives_ . The design of PODER was based on the voluntary participation of students and teachers. Lack of incentives combined with a strategy that rely on implementation during out-of-school hours was, perhaps, the single most important factor behind the low participation rates.

All these complex implementation challenges were compounded by the student-level randomization creating treatment and control groups within each school. This factor increased the role played by stigmatization and introduced further complications to the implementation of the Program, particularly in a large school setting. As it is shown in Figure 2, the take-up rates for the math tutoring were close to zero, therefore, _de facto_ , PODER consisted in a CBT-based intervention aimed at improving socio-emotional skills, improving math test scores and reducing school dropouts.

Despite the significantly low take up or compliance rates, the qualitative evidence presented in Cuevas and Silveyra (2018) shows that among those who had direct experience of the intervention there is a strong appropriation and willing to continue with the CBT-based workshops. During the fieldwork, interviews, workshops and satisfaction surveys were conducted and teachers expressed repeatedly that there is a need of training and coaching on how to develop socioemotional skills, not only for the students, but also for themselves. From the teachers’ point of view, there is a need of training and intervention designs in this issue that has not been filled by current training programs. Teachers and students identified PODER as a support and guideline to better understand their peers and improve the communication between teachers and youth. Not much can be said about the perception of teachers and students regarding the math tutoring since attendance was practically zero. Many school directors suggested that PODER be incorporated to the curriculum for it to be implemented during the conventional schooling hours or allow schools to decide when and under which format to implement the program.

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