Project Summary Protecting children through the primary prevention of child abuse and neglect (CAN) is a major priority given that an estimated 1 in 7 children are affected each year in the U.S. and the societal cost of CAN is of over $400 billion. Even though there are many evidence-based programs to prevent abuse, reduce harm, and treat trauma, there remain numerous barriers for policymakers to craft scientifically-informed policies to protect children. Accordingly, we propose an experimental study of a formal, theory-based approach for supporting policymakers’ use of scientific evidence that does not involve lobbying—the Research-to-Policy Collaboration (RPC) Model. The RPC fosters productive engagement between the policy and research communities by implementing systematic capacity building and outreach strategies. Previous experimental work on the RPC demonstrated the ability of this model to increase engagement between researchers and policymakers, increase policymakers’ value for research evidence, and improve their use of scientific evidence in their policymaking. We propose a state-level randomized controlled trial of the RPC (N = 30 state legislatures) that will evaluate the model’s ability to improve engagement between state policymakers and the science community, build policymakers’ awareness and value of CAN research, and subsequently increase their use of research evidence throughout the policymaking process. To accomplish this, we will test three specific research aims. Aim 1 will assess historical and current use of research evidence in state legislation pertaining to policies to protect children and provide equitable service delivery. This will involve qualitative coding of bills introduced by state legislatures over the last five years. Aim 2 will compare the frequency and quality of engagement with CAN researchers between the intervention and control conditions. Additionally, we will assess how the RPC model influences policymakers’ value and awareness of CAN research and evidence-based programs over time using a validated survey across three time points. Aim 3 will evaluate the effectiveness of the RPC on legislators’ actual use of research in legislation by observing and quantifying changes in legislator behavior related to research use. Improving the use of scientific information in policymaking can reduce population-level CAN and protect children by increasing the availability of evidence-based prevention programs and policies.