Why is it important to apply quantitative rigorous methods?

Justice systems comprise  many agencies working together - the police, prosecution, courts, prisons, probation, health and other social support  organisations.  It is hard to discern cause and effect!

Time plays a key role.  For individuals there are changes in behaviour that come with aging and life experience. For organisations, too, the processes involved  are generally multistage with decisions taken by different agencies and different times. The impacts of sentencing and effects of interventions  can  take  time to work through. This poses some tough challenges in how best to analyse the available data, to identify underlying principles and draw meaningful and robust conclusions.  Taking snapshots - cross sectional  views - of the system  provides limited understanding and is, at best, a poor guide to effective policy development.  On the other hand, in vivo longitudinal studies - ones that include time and are better placed to inform - are very difficult to implement, and results are often out of sync with political or policy need.  Simulations have the potential to offer some solutions to this challenge.

The simulations we use involve a layered architecture, with components covering different aspects of the criminal justice system:
The application of scientific, quantitative methods to questions of policy and practice in criminal justice