Peer Group Composition Constraints in Program Targeting
Restricting social program enrollment exclusively to high-risk youth maximizes direct statistical returns per slot, but risks concentrating negative peer dynamics, which can counteract treatment benefits.
Picture this
Think of placing all struggling students together in one isolated classroom; without high-performing classmates to set positive daily habits, the group can reinforce disruptive behaviors instead of learning constructive ones.
What the evidence says
While 100% of crime reduction cost savings ($652–$1,250 per participant) stem from the 3% at-risk subgroup, universal open-enrollment programs embed at-risk youth in a broader peer group where 97% of participants have no criminal record, preventing adverse peer contagion.
- Who
- N = 163,447 applicants (97% low-risk youth, 3% at-risk youth with prior arrests), New York City.
- How
- Theoretical and empirical evaluation of peer spillover dynamics in lottery slot allocation models.
What to do
1. Maintain a baseline proportion of low-risk peers in youth employment interventions to preserve constructive social norms and prevent negative peer spillover effects.
From the source
"Participation in SYEP could change the composition of a youth's peer group in a way that mitigates criminal justice contact, and the program might therefore have a different effect if it were offered exclusively or primarily to at-risk youth."
The_Effects_of_Youth_Employment_Evidence_from_New_York_City_Summer.pdf