Garnaut describes a few categories of economic modelling: The first category is ‘conventional market economic effects’, things you can measure and have data for. The scond category is ‘things you can measure and model but for which you have no real data’. Tourism falls into this category and so his core model excludes tourism for now. The third category is ‘things we value but that fall outside conteporary economic models’, things such as the Great Barrier Reef, which, when we lose them forever there’ll be a national sense of mourning. He emphasised that the numbers only tell a story in category one, tell a made up story in category two, and tell no story at all in category three.