PROJECT SUMMARY Few children between 2 and 5 years old in the US meet dietary guidelines.1–3 Further, 4 out of 10 children are overweight or obese by age 5.4 Consuming a healthy diet (e.g., fiber, antioxidant-rich foods)7–9 and maintaining a healthy weight9–11 provide significant protection against mortality and development of disease. Given that early life patterns track into adulthood,12,13 early interventions are needed to decrease the risk of developing obesity. Thus, early care and education (ECE) is a promising setting for obesity prevention. However, implementation of interventions in ECE remains a challenge. There are two crucial gaps to optimizing obesity prevention in ECE: 1) the lack of adaptive implementation strategies that tailor the intensity of implementation support delivery and 2) limited literature surrounding cost- effectiveness of obesity prevention and nutrition promotion efforts in ECE. The overarching goal of this application is to gather stakeholder perspectives on specification of an adaptive implementation strategy and acceptable cost-effectiveness thresholds for obesity prevention in ECE. To this end, we will focus on the evidence-based nutrition program Together, We Inspire Smart Eating (WISE). Compared to usual practices in ECE, WISE has demonstrated an increase in fruit and vegetable consumption at home for children,23 improvements in carotenoid intake,24 and reductions in fast food and sugar sweetened beverage consumption.23,25 Our prior work demonstrated that a package of 8 discrete, stakeholder- selected implementation strategies outperformed a basic implementation approach (i.e., training and reminders) for WISE. Given feasibility and potential prohibitive costs in the real-world, it is likely not possible to provide all implementation strategies to all sites in the future; in addition, all strategies may not be necessary to achieve the desired outcomes. Further, data on costs of WISE have not been examined. Future studies will need baseline comparator data to understand the costs and cost effectiveness of WISE without implementation strategy support to understand the relative benefit of implementation strategies such as adaptive approaches. Specific Aim 1. Determine key elements of an adaptive implementation strategy for WISE using stakeholder input. Stakeholder input on critical decision points, tailoring variables and decision rules will determine specification of an adaptive implementation strategy that can be tailored to site needs. Specific Aim 2. Estimate the incremental cost effectiveness of the WISE intervention compared to usual nutrition education. We hypothesize that WISE will be cost-effective compared to usual nutrition education when comparing each approaches’ ability to prevent BMI increases in children. Using secondary data, we will determine the cost per unit improvement in target child outcomes (i.e., BMI, servings of fruit/vegetables, carotenoid levels, junk food intake).