As we have seen earlier in this book, services are produced in a number of different ways ranging from individuals within a household to service TNCs with a global reach. While some modes of production function on a non-market basis e.g. self-service within households or via public services, e.g. education, social services, health care, the majority of services are produced within the context of the market. The market is usually divided into two main sources of demand: final consumption that stimulates the production of consumer services, and intermediate or business demand that stimulates the production of producer services. The supply side can also be characterised as a response to this dichotomy although, in practice, it is often difficult to assign firm outputs, for example, as responding either to intermediate or to final demand. It is often a mix of each (see Marshall et al., 1988) and has led some to question whether the concept of producer services as an identifiable and legitimate category of economic activity has been accepted too uncritically (Sharpe and Werneheim, 1996).