Background: This paper provides a comprehensive overview of the quantitative component of the Pacific Island Families #Study: Ala mo Tupulaga Pasifika Aotearoa (PIF: ATP; Life Course Trajectories for Young Pacific in Aotearoa), the latest follow-up of the longitudinal PIF birth cohort #Study, which employs a mixed-methods approach. Objective: This paper provides a comprehensive overview of the quantitative component of the Pacific Island Families #Study: Ala mo Tupulaga Pasifika Aotearoa (Life Course Trajectories for Young Pacific in Aotearoa), the latest follow-up of the longitudinal PIF birth cohort #Study, which employs a mixed-methods approach. Methods: The PIF #Study is a multidisciplinary longitudinal #Study that tracks the health and development of 1,398 Pacific children born in 2000 at Middlemore Hospital, South Auckland, Aotearoa | New Zealand. Data collection occurred at ten time points from infancy through young adulthood, with this assessment phase at ages 25–26 years, which aims to reach at least 750 participants. The assessments will take place at participants’ homes or at Auckland University of Technology, South Campus for those residing in Auckland. Data collection will be conducted across multiple sites, including Auckland, Wellington, Hamilton, and Whangārei in ANZ, as well as Brisbane, Sydney, and Melbourne in Australia. Physical measurements: weight, height, waist and hip circumferences, grip strength, body fat mass and muscle mass, blood pressure and pulse, glucose and lipid screening, and skin carotenoid concentration will be undertaken. Additionally, self-reported data will be collected on psychological wellbeing (e.g., depression, anxiety, and family functioning), nutritional and metabolic wellbeing (e.g., food intake and physical activity), and economic wellbeing (e.g., educational attainment, employment status, and job occupation and industry). Results: Data collection is scheduled to commence in June 2025 and conclude by December 2026. The first set of results and analysis is expected to be published from December 2027 onward. Reporting of all results will comply with the STrengthening the Reporting of OBservational studies in Epidemiology guidelines. Conclusions: This paper presents the #Protocol for the 25–26-year follow-up of the first Pacific longitudinal cohort #Study, which will comprehensively examine psychological, nutritional, metabolic, and economic well-being of Pacific young adults. With 25 years of longitudinal data and extensive expertise in life course #Research, this #Protocol outlines the design, methodology and scope of quantitative component of the PIF: ATP #Study. This phase is uniquely positioned to address key issues identified by Pacific communities and generate evidence to inform meaningful interventions and guide policy development while providing robust, contemporary, high-quality empirical evidence.

The selective revision of beliefs in light of new evidence has been considered one of the hallmarks of human-level rationality. However, tests of this ability in other species are lacking. We examined...