Research & Evidence

Evidence supporting a cohort-based, values-anchored program for adolescent girls during transitional periods.  

Our Longitudinal Research

The Academy at The Possibility Institute centers on a specific hypothesis: that a cohort-based, values-anchored program can meaningfully shift the trajectory of adolescent girls as they move through the transition from high school to college. Through The Academy, we are conducting a longitudinal research study that follows our cohorts as they progress through the program and into college. 

TPI’s longitudinal evaluation is organized around four validated measures: the EPOCH Measure of Adolescent Well-Being, the Flourishing Scale, the General Self-Efficacy Scale, and an adapted version of the Psychological Sense of School Membership scale. Each measure was selected because it captures a specific domain in which adolescent girls are currently under significant strain, and in which the existing literature on identity-anchored interventions shows the strongest evidence of impact. 

Late adolescence is a developmentally sensitive period. It is the period in which identity formation moves from broad exploration to deeper commitment, in which beliefs about one’s own capabilities begin to consolidate, and in which the social structures that hold a young person are vastly changing (Klimstra et al., 2010; Meeus, 2018; Bandura, 1995 ). 

For adolescent girls in particular, this developmental window is now overlaid with a pressing mental health crisis. CDC data show that 56% of female high school students reported significant depressive symptoms in 2021, and longitudinal analyses confirm that today’s adolescents face higher and rising rates of mental health problems compared to peers two decades ago (Centers for Disease Control and Prevention, 2021; Generational Shifts in Adolescent Mental Health, 2024). The Academy is built for this moment, and the research below highlights the empirical evidence for the design of The Academy - the cohort structure, the values work, and the timing. 

Evidence for The Design

The cohort is not just the delivery vehicle for the work. The cohort is the work. This is the core of what TPI means by community is the mechanism, and it is supported by a clear body of research on group-based intervention during adolescence. 

Adolescents internalize positive behaviors and attitudes most reliably when those behaviors are reinforced within peer groups (Prinstein & Giletta, 2016). Group-based experiences during adolescence draw on shared experiences to meet key psychosocial needs at this stage of development: belonging, cooperation, mutual support (Brown & Anistranski, 2020). The Positive Development Program for Adolescents (DPAR) in Spain demonstrated that a structured, cohort-based curriculum produced significant gains in self-esteem, self-efficacy, group identification, empathy, relational skills, and academic performance compared to the control group (Mendo-Lazaro et al., 2020). 

The longitudinal evidence is even more compelling. A 16-wave prospective cohort study from the Australian Temperament Project found that adolescent school belonging at ages 15 to 16 predicts mental health outcomes well into young adulthood, even after participants have left the school setting (Lim et al., 2024). In other words, the felt experience of belonging during this window appears to leave a durable mark - one that travels with a young person into the next phase of life. This is precisely the longitudinal effect The Academy hypothesizes for its cohort experience.

Belonging is also among the most pressing unmet needs in the current adolescent mental health crisis. Studies tracking adolescent peer relationships have argued that disruption in the quality of peer connection is a direct cause of the rise in adolescent mental health problems since 2010 (Peer Relationships Are a Direct Cause, 2024). A cohort-based program addresses this directly: it does not teach girls about belonging; it creates the conditions in which belonging can be experienced. The Psychological Sense of School Membership scale gives us a way to measure whether the cohort container is producing what the theory predicts.

The Cohort Structure

Values clarification - the process of identifying what matters and acting in alignment with it - is the inner thread that runs through every conversation in The Academy. It is also one of the most empirically robust mechanisms in well-being literature.

Recent work has shown that value clarity is a strong predictor of well-being and that changes in value clarity translate into changes in well-being over time (Smout et al., 2025). The values work is also what links inner growth to outer action. A girl can develop strong self-efficacy without a values foundation and end up with achievement without direction - which is the failure mode that affects many high-achieving young women entering college today. Conversely, a girl can have strong values but no belief in her ability to act on them. The General Self-Efficacy Scale captures the agency side of this equation; the Flourishing Scale captures the meaning and purpose side. The Academy is designed to build both together, because the research suggests neither alone is sufficient.

Recent work positioning flourishing education as a core component of the adolescent academic experience argues that today's adolescents need more than stress reduction - they need purpose, direction, community, and hope, and many youth themselves are drawn to forms of well-being that center on living in alignment with personal values, cultivating deep relationships, and contributing to the greater good (Advancing Adolescent Flourishing, 2026). This is the construct the Flourishing Scale was designed to measure, and it is the deliverable The Academy is designed to produce.

The Academy is not a traditional college-prep program, but it uses the college application process deliberately - as the real-life context in which the values work and the cohort work become consequential. This design choice is supported by the developmental research on transition periods and identity formation. 

Major transitions - including the move from high school to college - push adolescents into a new identity formation cycle (Identity: An International Journal of Theory and Research, 2025). Outside of structured transitional periods, adolescents may not feel a strong need to consciously engage with identity processes. The Academy meets girls in this moment, scaffolding discussions and exercises to help each girl articulate who she is, what she values, and what she wants.