Seminar: Why is crime in prison so high? Lessons from a change in prison regime

We provide experimental evidence that the high crime rate in prison is in large part due to the prison environment rather than to a selection effect. We exploit random assignment of inmates to wards in a penitentiary, and randomly pick one of two identical wings, each with two wards, to feature an alternative, more lenient prison regime, while keeping the other wing as control. Relative to the default regime, inmates in the treatment condition enjoy more autonomy and greater opportunities to stay in contact with family and friends outside the prison. Conditions such as number of personnel, recreational facilities, number of cells and floor plan were similar across the two wings. We find that recorded incidents of violent behavior, breakdowns and self-harm dropped substantially in the treatment condition relative to the control condition. A drop in violent behavior is confirmed by results from a of victimization survey that we conducted among inmates and among prison warders.