Artificial Inflation of a Delinquency Rate by a Selection Artifact

Cohorts of youths sentenced to a variety of correctional programs show substantial reductions in delinquent activity after leaving the programs compared to before sentencing. This paper develops models of delinquent activity and subsequent sentencing to a correctional program. We show how a population of youths, whose delinquent activity is represented by a stationary stochastic process, can be selected (using reasonable selection rules) to form a cohort which has an inflated rate of delinquent activity prior to selection. When the activity rate returns to its uninflated rate after the youths are released from the program, an apparent reduction results. Based on this analysis we conclude that the reductions noted in delinquent activity may be largely due to the way delinquents are selected for correction rather than to the effect of the programs.