ICH has been the evaluator for the BSAS-funded Overdose Data to Action (OD2A) program in Somerville and Cambridge since January 2020. OD2A is administered by the City of Somerville’s Department of Health and Human Services and the Cambridge Public Health Department, and engages two implementation partners, the Somerville Homeless Coalition and Fenway Health, to implement opioid overdose prevention trainings tailored to people who may experience increased overdose risk due to homelessness or housing instability. ICH developed an evaluation plan; an online system for implementation partners in each city to track training characteristics; and a post-training survey to evaluate participant knowledge and intended behavior change as well as gather demographic and drug use information. ICH’s ongoing work for the evaluation includes summarizing data from participant surveys and training information for reporting and to inform program improvements.