There was agreement that public health 'functions' form an important class, although there was some confusion regarding whether functions refer to the purposes of public health activities or the methods of intervention by which public health achieves its aims (see working definitions in Table 2) . 44 NPHP 1998. 45 The word 'function' is used here in the sense of 'the purpose, role or use of something'; thus, the function of public health is 'to protect and promote health, and to prevent illness, injury and disability' (NPHP 1998). There was also wide agreement that both 'health issues' and 'determinants of health' are central to public health, although there are differing views on the relative importance of individual determinants and how they should be structured at lower levels of the classification. The inclusion of a 'settings' class was also generally agreed.