DSMBs provide independent oversight for biomedical clinical trials, so as to ensure the safe and ethical treatment of research participants, data quality, and the credibility of study findings. Recently, the type of research monitored by DSMBs has been extended to include randomized clinical trials of behavior and psychosocial interventions in community-based and justice-based settings. Four topics are addressed in this paper: the challenges of implementing intervention studies in criminal justice settings, ensuring the safety of research participants, facilitating the implementation of research protocols and treatment interventions, and enhancing the scientific integrity of research findings. The paper concludes with recommendations that pertain to the data and safety monitoring process relevant to services research in general and to criminal justice intervention studies in particular. Two experiments are presented as case studies for more in-depth discussion due to their research design complexities, protocol implementation issues, and substantive interaction. One recommendation is to examine the utility of existing standard operating procedures, definitions, forms, and Web-based reporting applications of the DSMB. A second recommendation is to increase the use of standardized or common measures across studies in order to reduce the cost of infrastructure and allow the pooling of data for cross-study comparison and secondary analysis. Other recommendations pertain to agreement on a common set of performance-monitoring standards, the outlining of study-specific tables and figures in advance, the negotiation of memos of understanding with participating criminal justice and treatment agencies, and the requirement of power analysis based on evidence of a small effect size. 7 figures and 25 references