This project will evaluate batterer intervention systems with an eye toward teasing out the contributions of different parts of the system. The project will take advantage of the size of California's population currently in the criminal justice system and the length of its statutorily mandated batterer intervention programs ' the 52 week programs are among the longest in the country. The common statutory framework in California combined with the variation in the operation of courts and batterer treatment programs within that framework provides an ideal environment for conducting a quasi-experimental study, making it easier to distinguish the effects of specific components of batterer-intervention systems.
Various qualitative and quantitative measures will be used to examine the characteristics of different components of the systems and their interactions. A multi-method research design will begin by creating typologies of the batterer intervention system in six different jurisdictions in the state and the batterer intervention programs within these systems. Measures of program fidelity will be constructed so that outcomes may be evaluated relative to differences in program design and implementation.
Program completion ' a key element of compliance with the terms of probation ' and reduced recidivism ' specifically reduced recidivism for domestic violence offenses ' will be the key indicators of effectiveness and will be measured by tracking records from law enforcement, the courts, and batterer intervention programs. An estimated sample size of approximately 2,000 will be selected from batterers enrolled in intervention programs in six project sites.
The importance of determining what works and establishing more reliable evidence of effective interventions reaches well beyond California. The goal of this research is to assist in building a national consensus on the components of these systems that are most effective.