Intuitively this doesn’t make sense.
It seems more likely that Longer sentences are for more serious crimes or a history of crime and people who violate more serious crime or have a long history of crime are more prone to recidivate therefore juveniles with longer stays will probably recidivate sooner.
Juveniles with longer sentences are being compared to juveniles with shorter sentencing. It makes sense that the results show juveniles that receive a shorter sentence will have a lower recidivism rate.
A proper experiment would be to divide groups of juveniles eligible for long sentences into two comparable groups where one group receives the full sentence and the other group receives a shorter sentence and see how long it takes for each group to recidivate.
Study: Long-term juvenile incarceration fails to decrease reoffending rates — Center on Juvenile and Criminal Justice
— Read on www.cjcj.org/mobile/news/5476
More Juvenile Resources
https://www.aecf.org/m/resourceimg/aecf-juveniledetentionriskassessment1-2006.pdf
Future of Policing 