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The Akuna Model of the Australian Criminal Justice System. Dr Brent Davis Modelling and Forecasting Australian Institute of Criminology July 2008. AIC. Australian Institute of Criminology Australia’s national crime and criminal justice research agency Federal statutory authority
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The Akuna Model of the Australian Criminal Justice System Dr Brent Davis Modelling and Forecasting Australian Institute of Criminology July 2008
AIC • Australian Institute of Criminology • Australia’s national crime and criminal justice research agency • Federal statutory authority • Department of the Attorney-General
AIC • Five pillars of research • Crime monitoring • Crime reduction and review • Global, economic and electronic crime • Justice and crime analysis • Modelling and forecasting • Website: aic.gov.au
CJS Modelling • International – since late 1960s • United States: JUSSIM I and II; CJSSIM • Britain: CJRM • Canada: CANJUS • Netherlands: Jukebox • New Zealand: Pipeline • Sweden: SUMO
CJS Modelling • Australia – since the early 1980s • NSW: Adjudication • Vic: Prisons • Vic: Criminal Justice System • Vic: Crime Projection • Qld: Juvenile Justice • WA: Prisons
Motivations • Operational management & resource planning • Policy Analysis
Motivations • Operational planning and resource mgmt • Corrections managers • Prisoner arrivals, stocks, and departures • Victoria and WA prisons models • Police and prosecutions managers • Work load planning • Spatial distribution of policing resources • NSW BOCSAR Adjudication model
Motivations • Policy analysis • Sectoral specific, or whole-of-system • Better inform decision- and policy-makers • on options and implications of alternate courses of action • What if; Solver analyses • Qld: juvenile justice; Vic: whole-of-system
Types of CJS Models • Macro-simulation Models • Aggregate data (national, state etc) • Annual or quarterly frequency • National collection agencies (eg ABS) • Policy analysis models
Types of CJS Models • Micro-simulation models • Unit record data (individuals, families) • Monthly, weekly, daily frequency • Operational agencies (administrative data) • Operational mgmt & resource planning
Akuna Model • Objectives: • improve our understanding of the processes of the Australian CJS, and through this • make a substantive contribution to more robust evidence-based policy analysis of Australian CJS • Akuna is Australian Aboriginal word • means ‘flowing water’
Akuna Model • Policy analysis • What if; Solver • Macro-simulation • Whole-of-system • Stock and Flow • Readily available (ABS) data • Annual frequency
Akuna Model • Confronted several initial challenges • Model design • Data issues • (More to come as we progress !!)
Akuna Model • Challenge: model design • Economic and financial modelling bedevilled by debates over design issues • what to model; relationships between them • CJS modelling appears have convergence of thinking in model design • main sectors, elements, and relationships
Akuna Model • National Criminal Justice Statistical Framework (NCJSF) • NCJSF usefully informed our initial thinking on model design, and early development work
Akuna Model • NCJSF good general representation of • main sectors, elements and • flow relationships within CJS • Regrettably, matching data sets not yet available
Akuna Model • Challenge: data • Data for macro-sim CJS modelling not as readily available as for economic modelling • Generally annual – not much qtly or monthly • Limited historical – 4 to 5 years some elements • Calendar year and financial year
Akuna Model • Administrative By-Product (ABP) data • Primary motivation for collection • Operational mgmt & resource planning • Police; Courts; Corrections • Policy analysis applications ancillary • Analyst do best they can with what they get • Fortunately, CJS modellers are pragmatists
Akuna Model • Work started in March 2008 • Literature Reviews • International and domestic • More difficult to obtain than expected • Data collection • National collections (ABS) • But annual, not long historical
Akuna Model • Stock-take in May 2008 • Macro-simulation: whole of system • Policy analysis: what if; solver • Scenarios, not forecasts • Data organisation– compatibility (cal vs fin year); incidents vs persons; leakages between elements and sectors; stability of branching rates
Akuna Model • Five Sectors • Crime; Investigations; Adjudication; • Sentencing; and, Corrections • Branching rates determined probabilistically • Fairly stable across time • albeit short term
Future Directions • Near to Medium Term • Data extension (longer time horizons) • Trial runs of scenarios (what if; solver) • Peer and stakeholder consultations • Presentations and publications
Future Directions • Medium to Longer Term • New modules on • Economic Drivers of Crime • Demographic Drivers of Crime • Better understanding of • feedback loops (inc recidivism) • adjudication and sentencing processes
Conclusion • Very much welcome active engagement with peers and stakeholders • Especially for value-adding dialogues with other CJS modellers, and CJS model users brent.davis@aic.gov.au