Importance
Although school environments are thought to influence health behaviors, experimental data assessing causality are lacking, and which aspects of school environments may be most important for adolescent health are unknown.
Objective
To test whether exposure to high-performing schools reduces risky adolescent health behaviors.
Design
We used admission lotteries—which mimic random assignment—to estimate the causal effect of school environments on adolescent health. We surveyed 1270 students who applied to high-performing public charter schools in low-income minority communities in Los Angeles. We followed lottery “winners” (Intervention) and “losers” (Control) from the end of 8th grade/beginning of 9th grade through the end of 11th grade. Intent-to-Treat (ITT) and Instrumental Variables (IV) techniques estimate the effects of “winning” the lottery and attending high-performing schools on health behaviors and whether effects varied by gender.
Setting:
Charter and non-charter public high schools in Los Angeles.
Participants:
Students applying to one of the 5 public charter schools in Los Angeles where the majority enrolled were economically disadvantaged, the school’s academic performance ranked in the top tertile of LA County public high schools, there were at least 50 more applicants than seats available, and they used an admissions lottery.
Main Outcomes and Measures:
Primary outcomes were 30-day marijuana use and high-risk marijuana use. Additional health outcomes included 30-day alcohol use, alcohol misuse, ever being in a fight, ever having sex and past year delinquency. We also examined potential intermediate factors (time studying, truancy, school mobility, school culture, school order, teacher support, and proportion of substance using peers in students’ social networks).
Results
Intent-to-treat analysis showed that lottery “winners” (n=694) reported less marijuana misuse than loterry “losers” (n=576), as well as fewer substance using peers, more time studying, less truancy, greater teacher support, more orderly schools, and less school mobility(all p<0.05). Stratified analyses suggest more consistent effects for boys with treatment effects noted as early as 9th grade.
Conclusions and Relevance
This natural experiment provides evidence that school environments can improve risky behaviors for low-income minority adolescents.