DATA & METHODS CORE ABSTRACT Researchers and policymakers need better data, improved methods, and rigorous analysis to best determine which policies and initiatives are, or could be, effective in addressing the nation’s opioid-related public health crisis. Research assessing the effectiveness of specific opioid policies and initiatives has surged, but much of this work uses accessible existing policy datasets and familiar difference-in-difference and interrupted time series analysis. Multiple studies have identified shortcomings of these methods in the presence of heterogeneous treatment effects and policy endogeneity. Furthermore, while researchers have begun to pay greater attention to inconsistencies in how opioid policy data are defined and operationalized, far less attention has been given to the differential impacts the same policies have on different communities in light of vulnerabilities and structural factors that lead to differential policy experiences. There is also increasing evidence that the community environment itself influences opioid misuse and harm, raising questions about how effective different opioid policy strategies might be given interactions with local factors. These conceptual and methodological challenges need to be clearly defined and communicated to all those working in this policy space. As a national resource, OPTIC has actively addressed this need, and OPTIC’s Data & Methods Core (DMC) plays an essential role in that effort. Internally, the DMC maximizes the efficiency and quality of Center work by providing the data, tools, and methodological support necessary to conduct high-quality, innovative research. Externally, the DMC is a reliable resource for the scientific community, providing data to support studies of policy effects and community vulnerabilities, publishing educational resources on data and methods to enhance the rigor of such studies, conducting trainings for junior investigators developing research in this area, and disseminating information on best methodological practices for evaluating policies affecting opioid- related outcomes. The DMC will continue updating, tracking, gathering, and documenting opioid-related policies and their specific components and timelines on a state-by-year basis (2000-2027). We will update our comprehensive literature review on the use and/or effectiveness of federal and state policy approaches to the opioid crisis, retaining our focus on the methodological rigor of the evaluations with additional attention to differential effects of policy by race/ethnicity, socioeconomic status, and types of drug misuse affected by the policy. We will identify, construct, and assess metrics that capture the high risk of discriminatory implementation and enforcement of opioid policies within communities, and we will continue to assist the OPTIC community in the development and testing of new methods for dealing with complex and dynamic policy environments.