Research Brief: The Effects of Youth Incarceration in Adult Institutions on Future Incarceration.

Article: Silver, Ian A., Vaidya, Prarthana, and Wooldredge, John. 2025. “The Effects of Youth Incarceration in Adult Institutions on Future Incarceration.” Journal of Criminal Justice, 98, 102426. https://doi.org/10.1016/j.jcrimjus.2025.102426.

1. Background (PDF and Article)

Thousands of adolescents are sentenced to serve time in adult jails and prisons each year. While the number of youth incarcerated in adult facilities has substantively reduced over time, the practice still exists, potentially resulting in kids as young as 12 being incarcerated alongside adults. Many of these youth were not charged with committing violent offenses, but rather were transferred to the adult system due to prosecutorial or judge discretion. These facilities, built and operated for adult populations, often subject youth to violence, neglect, and isolation—conditions that mirror or intensify adverse childhood experiences (ACEs). Due to the well documented link between ACEs and future criminal legal system (CLS) contact, incarceration in an adult facility during adolescence (and exposure to additional ACEs) could potentially be criminogenic, exacerbating antisocial behaviors and leading to future system involvement. However, limited research has considered youth incarceration in an adult facility as a mechanism that could exacerbate antisocial behaviors. This study sought to address this gap. The study assessed if youth incarceration in an adult facility predicts the number of months until the first period of incarceration after the age of 18. As discussed below, the results of the study suggested that incarceration in an adult facility before 18 could be criminogenic and amplify antisocial behaviors.

2. Summary of Findings

The results suggest that incarcerating youth in adult facilities increases the likelihood of and decreases the time until incarceration after the age of 18, suggesting a potential criminogenic effect. Three findings are highlighted:

First, youth incarcerated in adult jails or prisons experienced a 90% reduction in the number of months until being incarcerated after the age of 18 when compared to youth with no CJS involvement. On average, their first post-18 incarceration occurred 2.2 years earlier than youth with no juvenile involvement.

Second, while being arrested and incarcerated in a juvenile facility before 18 were also associated with reduced time to adult incarceration, the magnitude of the TR ratio was substantively smaller than adult facility confinement before 18. Youth arrested experienced a 20% reduction and those placed in juvenile facilities had a 70% reduction in the number of months after one’s 18^th birthday until adult incarceration.

Finally, the results were consistent across analytical models. Using both traditional regression and a gradient-boosted multi-group propensity score weighting approach. Youth incarceration in adult facilities before age 18 consistently showed a higher likelihood of and earlier incarceration after the age of 18. These findings persisted even when weighted to limit differences between the youth without CLS involvement, youth arrested before 18, youth incarcerated in juvenile facilities before 18, and youth incarcerated in adult facilities before 18.  

3. Implications

This study adds to a growing body of literature suggesting that youth placement in adult jails an prisons may do more harm than good—for both the individual and public safety. The findings suggests that youth incarceration in adult facilities might increase CLS involvement in adulthood beyond youth incarceration in a juvenile facility and youth arrest before 18 – an apparent criminogenic effect. Importantly, any CLS during adolescence appeared to have some criminogenic effects, with the strongest being associated with youth incarceration in adult facilities.

Given this evidence, policymakers should consider further limiting the number of youth transferred to the adult system as it could harm both the youth and the community – through future criminal behavior. Judges and prosecutors must be cautious about transferring youth to adult court, particularly for non-violent offenses, and should be encouraged to rely on rehabilitative or community-based alternatives. Expanding community-based diversion programs, restorative justice initiatives, and cognitive behavioral therapy could help diminish the likelihood of adulthood involvement in the CLS for previously adjudicated youth. In cases where youth must be detained, youth should be placed in a juvenile facility until developmental processes conclude (18-25 years of age) and transferred to an adult facility to serve the remainder of the sentence.

To diminish the criminogenic effects of adult facilities on youth, jails and prison should provide continuous evidence-based treatment and effective reentry support specifically designed for detained youth. This includes programs such as Cognitive Behavioral Interventions-Core Youth (CBI-CY) and Aggression Replacement Training (ART), as well as job placement services, mentoring, and housing assistance.

4. Data and Methods

This study draws on data from the National Longitudinal Survey of Youth 1997 (NLSY97), a nationally representative panel study of 8,984 individuals born between 1980 and 1984. The analytical sample included only youth who turned 18 after the baseline interview in 1997, which ensures that key predictors were measured before the outcome period began (N = 8,961).

The primary independent variable identifies whether a youth was incarcerated in an adult jail or prison before the age of 18. The main outcome measure is the number of months until the first incarceration after turning 18. To address confounding, the authors controlled for key covariates such as the number of arrests before 18, incarceration in a juvenile facility, self-reported delinquency, parental incarceration, household socioeconomic status, peer behavior, school engagement, and demographic characteristics.

Missing data on covariates were imputed using random forest multiple imputation. The statistical analysis employed a parametric survival model using a lognormal distribution, which best fit the distribution of the number of months until incarcerate after the age of 18. A replication was conducted using gradient boosted multi-group propensity score weighting, which balanced the covariates across four groups: those with no CJS contact, those arrested but not incarcerated, those incarcerated in juvenile facilities, and those incarcerated in adult facilities before 18. Both analytic approaches yielded evidence suggesting that incarceration in an adult facility before the age of 18 resulted in an increased likelihood of incarceration after 18 and a decreased number of months until the first period of incarceration.

5. Conclusion

Youth transfer to adult courts is not merely a response to severe criminal behavior, but can be implemented at the discretion of court actors. While the elevation of these charges might appear necessary, a growing body of literature suggests that youth incarceration in adult facilities could cause harm to the youth and the community. The experience of confinement in such institutions functions as a ACE, accelerating the path to adult incarceration and compounding long-term disadvantage. These findings bolster calls for juvenile justice reform, urging policymakers to curtail the confinement of youth in adult facilities and expand existing rehabilitative efforts.

Disclosure: This research brief was prepared by ChatGPT and reviewed/edited by Ian A. Silver.