Individual vulnerable groups described as Population Groups classified by other classes (e.g. person-level demographic descriptors in 'determinants of health'). Actions described as instances of Public Health Activities. Core function nine (shaded in Table 5 ) 'Promote, develop and support actions to improve the health status of Aboriginal and Torres Strait Islander people and other vulnerable groups' identifies important target populations, rather than describing a separate function of public health. Functions, methods, and population groups thus form three distinct dimensions (among many) of interest in a multi-dimensional classification of public health.