An introduction to population health science -- Conceptualizing and evaluating causes for population health science -- The causes of cases versus causes of incidence -- Population health across levels, systems, and the lifecourse -- Ubiquity and the macrosocial determinants of population health -- Causal architecture to understand what matters most : theory -- Causal architecture and what matters most : quantitative examples -- Valuing population health interventions, measuring return on investment -- Equity and efficiency in population health science -- Prediction in population health science -- Case study : can we reduce obesity by encouraging people to eat better? -- Case study : simulating the impact of high-risk and population intervention strategies for the prevention of disease -- Tensions in population health science