School dropout remains a significant issue. In 2018, over 2 million youths aged 16 to 24 lacked a high school diploma and were no longer enrolled in school. Among the programs funded by the U.S. Department of Education to address this challenge is the Peer Group Connection-High School (PGC-HS), a school-based peer mentoring program designed to facilitate the delicate transition from middle school to high school for ninth-grade students. Mentors are tasked with creating a supportive environment where students engage in a curriculum of group activities tailored to address the challenges linked to this transition. This curriculum places emphasis on developing critical thinking, sound decision-making, a sense of belonging, positive relationships, and motivation.

In randomized controlled trial (RCT) involving six public high schools in North Carolina, the program was implemented over three academic years, spanning from 2016 to 2019. A total of 1351 students were randomly assigned to either the experimental group (n=680) or the control group (n=671). However, out of the 680 ninth-grade students allocated to the PGC-HS (treatment) group, only 412 met the compliance criteria by attending a minimum of 14 outreach sessions. To assess the  program's effectiveness,  various  academic, behavioral, and noncognitive outcomes indicative of school engagement and academic achievement were analyzed using  both administrative records and self-reported data.

The results exhibit variations across the analyses, yet there is a consistent trend indicating that the program might have a favourable impact on suspension (-7%), disciplinary referrals (-5.7%), and students' perceptions of school engagement. Further support from dosage analyses suggests that full program participation may also be linked to improvements in GPAs (+0.15 grade points), decision-making skills, and academic achievement-related peer norms. In conclusion, the researchers propose that, despite the limitations associated with the statistical assumptions of the CACE methods used, the results imply the program's potential effectiveness, particularly for students who participate more actively, as indicated by the positive impact on several academic, behavioral, and noncognitive measures.