As has been shown, the open access cases raise an allocation issue, in the absence of a market price for them, by which to establish their opportunity cost in an alternative use. Taking rural land resources as an example, in a competitive market the demand for land for commercial development, including tourism, say a hotel or leisure complex, will nearly always outbid demand for agricultural land as the returns will far exceed those of farming. Where land has traditionally been used for informal recreational purposes, it carries no price as an indicator ofits value, yet it is likely to have a high social one. In short, a comparison of the commercial and social value of amenity land is not conducted on a comparable basis. Thus, there is a need to devise ways of assessing the demand for and value of such non-priced resources.
Conversely, to an extent, there is a market for assessing the social benefits and costs of extemalities and appropriate policy instruments to enhance their benefits or mitigate their costs. The methods advocated by economists to estimate the values of public goods and the instruments to deal with extemalities are examined in the next chapter, using illustrative examples relating to tourism.