Article A Method for Analyzing Changing Prison Populations: Explaining the Growth of the Elderly in Prison

Background: For the past several decades, the U.S. prison system has witnessed a steady and persistent increase in the ages of prison populations. Given the additional costs and burdens placed on prisons as they house older inmates, this aging trend has generated intense interest among policy makers and academics who seek to understand why prison populations are getting older. Objective: This article presents a method for evaluating drivers influencing the change in age distributions among prisoners. Method:We define a methodological approach and demonstrate its appli-cation using prison data from four states reporting to the Bureau of Justice Statistics ’ National Corrections Reporting Program. Results:We find that since 2000, the primary driver of overall growth in the elderly populations in prison (defined as inmates over 50) is the increasing admission age of offenders entering prison. Moreover, changes in offense mix and sentence length/time served over the last decade have had significantly less influence on the age composition of prison populations. We also find that the impac