ABSTRACT The opioid crisis is the result of a dynamic process that has been evolving for at least two decades. Tackling the crisis requires a multi-pronged approach that both accounts for illicit opioid markets and carefully considers contributing factors at each stage in the potential pathway from opioid initiation to opioid harms. There has been a substantial increase in research studying the effectiveness and unintended consequences of specific opioid policies and initiatives. However, the complex policy environment, rapidly evolving nature of the crisis, potential interactive effects of concurrently passed policies, as well as variation in policy implementation create significant methodological challenges for policy evaluations. To address these limitations, the objective of the COPR Data and Methods Core (DMC) is twofold: 1) build the essential infrastructure for maximizing the efficiency, consistency, and quality of the data and research throughout COPR; and 2) provide a key resource to the broader scientific community by providing the data needed for policy evaluation, supplying educational resources on necessary additional controls for understanding the opioid environment, and producing information on optimal methodological practices for evaluating opioid policies. The DMC?s multi-disciplinary team will compile multiple databases, undertake multiple causal inference techniques to help develop a set of methodological guidelines to enhance the scientific rigor of opioid policy research, and serve as a valuable resource for the development and dissemination of educational materials related to the Center?s data, methods, and tools. Databases will include findings from a comprehensive review of the literature on the effectiveness of different policy approaches to the opioid crisis, whereby our team will identify and code relevant literature through a systematic review to develop an inventory system for flagging articles of particular types (e.g., using particular causal methods, focused on a particular policy) to support understanding what is currently known and unknown about the effects of interventions aimed at addressing the crisis. We will also assess, gather, and prepare raw policy data, covariates, and outcome data on a state-by-year basis (2000- 2020); this substantial undertaking, which will result in a publicly available comprehensive data repository, will serve as a valuable resource for researchers and the broader scientific community. Leveraging these rich data sources to examine associations between policies, specific policy components, and opioid outcomes, will both provide methodological assistance to Research Projects and facilitate development and testing of new strategies for causal inference. By creating distance learning website, policy briefs, workshop materials, and training materials for the Data Library, methods, and tools coming from the DMC and COPR Projects, we will ensure broad dissemination of critical tools and information through a single resource from which data and methods can be drawn to test innovations as they are implemented at local, state, and federal levels, and to advance our understanding of best research practices and policy efforts to combat the opioid crisis.