Simulating prison populations


Applied Research Services, Inc. (ARS) is a national consulting firm based in Atlanta, Georgia that specializes in criminal justice research, evaluation, and policy development. The staff are quantitative criminologists who work with clients across the nation on various criminal justice related projects.

John Speir, Managing Partner at ARS details how SIMUL8 has added an entirely new dimension of decision-support to prison population projections and policy analysis.

Applied Research Services

The Challenge


Many jurisdictions face the daily challenge of avoiding a prison-crowding crisis. Their policy makers have two options: (1) to predict, fund, and build adequate space for their impending demand, or (2) take the necessary policy or legislative steps to reduce the number of inmates entering prison and/or reduce how long inmates stay.

Unfortunately prison populations vary naturally over time for a number of reasons::

  • changes in prison admission patterns
  • changes in the demographic make-up of offenders
  • changes in sentences imposed by judges
  • changes in resource allocation and prison capacity
  • and annual legislative changes to criminal sanctions

Together, these factors interact in a dynamic system that complicates the efforts of planners to manage the growth of prison populations and to ensure prison beds are in place at the time beds are needed. Building too many prisons can be a costly investment, while building too few prisons can be a costly mistake that typically results in extensive social and legal costs (law suits, riots).

On average, it cost about $75 million to build one prison to house 1,500 offenders and more than $25 million to operate annually. In Georgia, for example, where the prison population exceeds 48,000 inmates, slight changes in sentencing practices or changes in parole release policies can have a profound impact on the prison population and state budget.

The Solution

For the most part, states are still relying on statistical projections or were dependent on out of date simulation software or spreadsheets simulations. To assist in making such critical policy decisions, public policy planners are using ARS SIMUL8 simulation models.

ARS specializes in building simulation models that mimic the flow of offenders into, through, and out of the state correctional systems, beginning with conviction and continuing with discharge from the the correctional system.

ARS's simulation models provide the ability to analyze the impact of changes in operating policies, sentencing practices, post release practices, and external system pressures on the system. This includes, for example, the projected impact of different sentencing models (guidelines, determinate, or indeterminate) on institutional bed space, jail backlog, correctional alternatives, resource allocation, specialized services (medical and mental health), and prison admissions and commitments.

The Result

SIMUL8 has added an entirely new dimension of decision-support to prison population projections and policy analysis. SIMUL8 has provided greater predictability in knowing the short and long-term impact of policy and budgetary decisions. In one particular project, if the client would have adopted the new sentencing system as originally proposed, this system would have cost the taxpayers an additional $250 million over the current system without any improvement in public safety.

The benefits are not only financial. Knowing how many prisons are needed and when they will be needed not only saves money but it also offers public safety. When beds are not available, policy makers resort to other methods to reduce the pressure on the system, such as accelerated parole release.

ARS are now moving simulation into other criminal justice areas, including court case flow management, jail booking and prison classification processes, inmate pick-up and delivery, and others.

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