The Calculator works out the total costs to society as a whole of pathways generated by users essentially because working out the impacts of specific policies in terms of taxes or subsidies, and the costs and distribution of these policies, is beyond the scope of the model. The 2050 Calculator is intended to be a simple model; it does not model the markets and relationships which would be needed to work out this level of detail. Furthermore, the Calculator is designed to be policy neutral. The model does not inform on how pathways might be acheived, only the potenial for what could be acheived. For this reason, it is more consistent to calculate costs at the broadest level.