This study explored the competencies required for informal community leaders to effectively promote health within Thai communities, employing an exploratory sequential mixed-methods design. The qualitative phase, comprising in-depth interviews with thirteen community leaders, identified four critical domains of competency: basic health knowledge, communication skills, network building, and cultural awareness. These domains were subsequently validated through second-order confirmatory factor analysis, which confirmed their reliability and construct validity. The findings highlighted the pivotal role of these competencies in enabling community-led health promotion initiatives. This research provides a robust, evidence-based framework to inform the development of training programs, policy strategies, and targeted interventions aimed at enhancing health outcomes within Thai communities.

South Korea has experienced rapid economic development since the 1960s. However, pronounced regional disparities have concurrently emerged. Amid the escalating regional inequalities and persistent demographic challenges characterized by low fertility rates, regional decline has become a pressing issue. Therefore, the feasibility of expanding transportation networks as a countermeasure to regional decline has been proposed. This study utilizes the synthetic control method and spatial difference-in-differences methodologies to assess the impact of the 2017 opening of Seoul–Yangyang Expressway on economic development and population inflow within Hongcheon-gun, Inje-gun, and Yangyang-gun. The purpose of this study is to evaluate the effectiveness of highway development as a policy instrument to mitigate regional decline. Findings from the synthetic control method analysis suggest a positive impact of the opening of the expressway on Hongcheon-gun’s Gross Regional Domestic Product (GRDP) in 2018, as well as Yangyang-gun’s net migration rates from 2017 to 2019. Conversely, the spatial difference-in-differences analysis, designed to identify spillover effects, reveals negative impacts of the highway on the GRDP and net migration rates of adjacent regions. Consequently, although targeted transportation infrastructure development in key non Seoul Metropolitan cities may contribute to ameliorating regional imbalances, results indicate that such measures alone are unlikely to suffice in attracting population to small- and medium-sized cities outside the Seoul Metropolitan Area.