A Spatial and Temporal Analysis of the Impact of a Community Court

Barbara Parthasarathy, The Urban Institute

The presentation will show the impact of the community court in the North and Northeast (N/NE) precincts in Portland, Oregon. The Portland Community Courts (PCC) offer alternative sentences and services to offenders convicted of quality-of-life crimes, such as vandalism, theft, and prostitution. This evaluation is designed to measure the impact that community court interventions have on multiple indicators of the quality of life in the targeted communities. It will incorporate both a time series and spatial evaluation of the program's effects, using data provided by the Portland Police Bureau for all arrests in Portland between January 1, 1996 and January 30, 2000. The hypothesis tested is that arrests for crimes eligible for participation in the N/NE Community Court will be lower in the period followng the implementation of the court, compared to the levels pre-implementation. Two methods will be employed to measure changes in arrests. First, ARIMA intervention models will be used to measure changes in the aggregate number of arrests over time, controlling for other factors, such as seasonal effects and general changes in policing during the full period of observation. Second, the PCC effects on the spatial dynamics of crime before and after implementation in areas with a high concentration of target crimes will be studied, to identify changes in the distribution of arrests.

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Updated 05/20/2006